North America > United States

Great Salt Lake

lakeGreat Salt Lake
countryUnited States
surface area6,479 km2
maximum depth12 m
average depth4 m
lake typeEndorheic, hypersaline
length121 km
width46 km
catchment area86,896 km2
altitude1,282 m
volume23 km3
inflowsBear, Jordan, Weber rivers
islandsVaries between 8 and 15
shore length803 km
settlementsSalt Lake and Ogden metropolitan areas.
residence time1,230 days
average discharge215 m3 / sec.

Great Salt Lake Information and Facts

The Great Salt Lake is the eighth largest endorheic lake in the world and the largest lake in the United States located west of the Mississippi River. It’s typically 3 to 5 times saltier than the ocean and is one of the biggest migratory bird magnets of Western North America.

Remnant of Lake Bonneville

Great Salt Lake is the remnant of the prehistoric Lake Bonneville, which occupied ten times the surface of today’s lake and was 58,000 km2 at its greatest extent. The lake had a maximum depth of 281 meters and covered much of present-day Utah, as well as small portions of Idaho and Nevada during the ice ages of the Pleistocene Epoch. The old lake existed until approximately 16,800 years ago, when a large portion of it was released through the Red Rock Pass in Idaho. Due to climate change Lake Bonneville also began to dry up, leaving behind Great Salt Lake, Utah Lake, Sevier Lake and Rush Lake.

Historic Facts

Although the lake was well-known to local Native Americans for centuries, it was first recorded by Silvestre Velez de Escalante in 1776, who learned of its existence from the Timpanogos Utes. Since no official name was given to the lake, the cartographer of the exhibition, Bernardo Miera y Pacheco, omitted showcasing it on the map he drew. In 1824 the lake was once again observed independently by Jim Bridger and Etienne Provost. The next ones to see it were illiterate trappers, which didn’t note it down. Because of various oral and written reports, errors were made regarding the documentation of Great Salt Lake.

Escalante only visited the shores of Utah Lake, and named it Laguna Timpanogos. The first to document it wrongly was Miera, followed by other cartographers who all put Timpanogos as the largest lake in the region and people wrongfully interpreted it as Great Salt Lake.In time this name was dropped from the maps and its original association with Lake Utah was forgotten by many.

The first scientific expedition to the lake, which managed to survey a part (but not all of Great Salt Lake) took place in 1843 and was led by John C. Fremont. The lake was entirely surveyed 7 years later in 1850 by Howard Stransbury, the man who also came across and later named the Stransbury Mountain Range and Stransbury Island.  The works of Fremont were barely published after Stransbury’s successful expedition. Stransbury’s published formal reports were well-received by the public and were very popular at the time. Besides geographical facts, it also included a discussion of Mormon religion practices based on personal interactions with the Mormon community of Great Salt Lake City, established in 1847.

In the November of 1895 Alfred Lambourne, the infamous artist and author, spent a whole year on Gunnison Island, writing a book of musings and poetry entitled Our Inland Sea. He even mentioned the guano sifters who came in March to harvest and then sell the guano of the nesting birds, used back then as a fertilizer. He left the island together with a group of guano sifters in the winter of 1896.

Geographic Facts and Islands

Occupying a shallow playa in the northern part of the US State Utah is the largest saltwater lake in the western hemisphere, Great Salt Lake. Because of its shallowness the lake’s size fluctuates a lot, however the average lake area is about 4,400 km2. The historic high was recorded in 1988 and measured 8,500 km2, whilst the historic low was seen in 1963 with a size of 2,460 km2.

It is the largest lake in the United States not part of the Great Lakes, and it is also the largest remnant of Lake Bonneville, a prehistoric pluvial lake once covering Western Utah. The lake lends its name to Salt Lake City (originally called Great Salt Lake City, named by the President of The Church of Jesus Christ of Latter-Day Saints called Brigham Young, who led his group of Mormon pioneers to the valley on the 24th of July 1847).

Great Salt Lake lies on the border of 5 counties: Box Elder, Davis, Tooele, Weber and Salt Lake. Salt Lake City can be found in the southeastern part of the lake, bordered by the Wasatch Mountains, while the Bonneville Salt Flats can be found to the west. The lake is bordered by the Quirrh and Stansbury Mountains to the south.

An uncertain number of islands dot the waters of the lake. During high water levels, most of them are islands, however when the water levels decline, they turn into peninsulas. According to the US Geological Survey and the US Department of the Interior 8 named islands can be found on the lake, which have never been totally submerged in historic time. However, all of them have been connected to the mainland during periods of low water levels. Besides these, a large number of reefs, shoals and rocks (with names like Strongs Knob, Gunnison Island, Goose Island and Egg Island) can be found on Great Salt Lake, which become fully or partially submitted under water.

The Utah Geological Survey proclaims there are 11 recognized islands (7 in the southern, 4 in the northwestern part). Antelope, Stansbury, Fremont, Carrington, Dolphin, Cub and Badger are the islands found in the south.  

Black Rock, Antelope Island, White Rock, Egg Island, Fremont Island and the Promontory Mountain Range are said to be extensions of the Quirrh Mountain Range, dipping beneath the lake on its southeastern shore. Stansbury, Carrington and Hat Islands, on the other hand, are the extensions of the Stansbury Mountain Range, while Strongs Knob is the extension of the Lakeside Mountains on the western shore of Great Salt Lake. Scientists proclaim that the lake is deepest in-between these islands, with a maximum depth of 10.7 meters and an average depth of 4 meters.


The lake is fed by three major tributaries, the Jordan, Weber and Bear Rivers, which deposit an estimated 1.1 million tons of minerals in Great Salt Lake yearly. These three rivers are all fed either directly or indirectly from the Uinta Mountain Range, situated in the northeastern part of Utah. The Jordan River doesn’t receive its water directly from the Uintas, but flows from the freshwater Utah Lake, which is fed by the Provo River and which actually originates from the Uinta Mountains. The Weber River starts on the northern slope of the Uinta Mountains, similarly to Bear River. The former enters Great Salt Lake on the east, whilst the latter flows in from the northeast.

Since the lake is endorheic and has no outlet, it boasts as very high salinity and is unusually dense. Its mineral content is steadily increasing and swimming in the lake is similar to floating, especially in the Gunnison Bay area, which is much saltier than the northern arm.

The levels of the water have been measured for more than a century, and recorded since 1875, always averaging 1,280 meters above sea level. But due to its shallowness, even small variations in water levels affect the extent of the shoreline. The waterflow is also influenced by the amount of flow diverted for agricultural and urban uses, especially in the case of the Jordan and Weber rivers.

A study conducted in 2014 by using three rings created a 576-year record of the levels of Great Salt Lake. It showed that the changes in the lake levels have been strongly modulated by the Pacific Ocean. The whole region is characterized by decadal-scale wet-dry cycles and atmospheric oscillations at low frequency. By capturing these climate oscillations researchers could predict the level fluctuation for 5-8 years in the future. The study also showed that Great Salt Lake differs in elevation between its southern and northern parts, as the former is 15-61 centimeters higher than the latter.

Lake-effect Precipitation

Due to the warmth of the water in Great Salt Lake, lake-effect snowfalls can be seen frequently. As the cold north and north-west winds blow across the lake, the difference in temperature between the warm waters and the cool air often form clouds that form precipitation downwind of the lake. These precipitations are generally heaviest from the Eastern Tooele County into Central Davis County.

The lake-effect snowfalls typically occur in late fall, early winter and early spring. During the summer the temperature differences lead to thunderstorms which drift eastward along the Northern Wasatch Front. The heavy rainstorms occurring in spring and autumn are also partly credited to lake-effect storms. Around 10% of the average precipitation in Salt Lake City is attributed to lake-effects.

Water Composition

A study made by the US Fish and Wildlife and the US Geological Survey showed that the lake has the highest level of methyl-mercury the researchers had ever seen, 25 nanograms per liter of water. The extreme concentration of methyl-mercury was found below the lake’s anoxic deep brine layer at a depth of 6 meters, although concentrations are already moderately high in the stratus where oxygen is abundant and brine shrimp are supported. Later studies achieved a health advisory warning for hunters not to eat the common goldeye or northern shovelers. According to a study made in 2010 the main source of mercury doesn’t come from local sources, but from the worldwide industry. 16% of the mercury flows in via the rivers and streams, while 84% comes from the atmosphere.  


Most of the salts which are dissolved in Great Salt Lake end up deposited in desert flats. Although the historic Lake Bonneville was fresh enough to support fish, plenty of salt is added into the lake yearly through rivers and streams, even though the amount is much less than the relict salt from Bonneville.

The lake’s main basin, Gilbert Bay, faces a highly variable salinity, influenced by lake levels and ranges from 50 to 270 parts per thousand. In comparison the average salinity of the World Ocean is 35 ppt, whilst the Dead Sea boasts 330 ppt. The ionic composition of the lake is similar to that of the seawater. Compared to the ocean, Great Salt Lake’s waters are slightly depleted in calcium and enriched in potassium.

Between 4.5 and 4.9 million tons of salt are deposited in the lake, of which about 2.2 million enter yearly from underground and surface streams and rivers. Out of this the salt industry extracts approximately 2.5 million tons of sodium chloride annually.

Flora and Fauna

Those parts of the lake which have a high salinity concentration don’t house many species, except for the brine shrimp, brine flies and numerous types of algae. There’s an estimate 100 billion population of brine flies at Great Salt Lake, which are the main source of food for birds.

The part of the lake which receives fresh water (eastern and northern areas) represents a critical habitat for millions of migratory birds in Western North America. These marshy areas make up 75% of Utah’s wetlands. Wilson’s phalarope, red-necked phalarope, American avocet, black-necked stilt, snowy plover, western sandpiper and ducks and geese are the most commonly sighted marshland birds.

In aim of protecting these birds, 27 private duck clubs, 7 state waterfowl management areas and a large federal bird refuge have been set up on the shore. The Bear River Migratory Bird Refuge, Gillmor Sanctuary, Salt Creek and Great Salt Lake Shorelands Preserve are only a couple of these reserves.

Numerous islands of the lake, including Gunnison and Cub Island, are ideal nesting places for the birds. To protect them properly (especially the nesting colonies of the American White Pelican) access to these islands is limited. Some of these islands also provide a proper habitat for lizard and mammalian wildlife, along with a variety of plant species. Explorers who visited in the mid-1800s noticed an abundance of yellow-flowered “onions”, a plant called Calochortus Luteus, a species only found in California today. The lake is home to the largest staging population of Wilson’s phalarope in it western side. Great Salt Lake was designated a part of the Western Hemisphere Shoreland Network in 1992.

Fish only appear at Bear River Bay and Farmington Bay when spring runoffs bring fresh water into Great Salt Lake. Brine shrimp, brine fly, protozoa, rotifers, bacteria and algae inhabit the lake waters.

Because of the railroad causeway the lake is separated into two different parts of which one is much saltier than the other. The water’s color south of the causeway has a greenish color due to the phytoplankton community dominated by green algae. On the other side, north of the causeway, the lake is dominated by a species of algae called Dunaliella Salina, releasing beta-carotene and bacteria-like haloarchaea, giving the water a red-purplish color. This type of bacteria actually converts non-toxic mercury into toxic methyl mercury, which makes its way into the southern part of the lake.

Diversity of organisms is much higher in the southern part of Great Salt Lake, which receives fresh water from its tributaries. During the spring snowmelt the salinity in this region can approach that of a freshwater lake. Invertebrates such as gnat larvae and back swimmers are fed upon by the shorebirds and waterfowl, whilst fish are fed upon by diving terns and pelicans.

The Solitary Pink Floyd

A solitary Chilean Flamingo named after the English rock band was a huge tourist attraction at Great Salt Lake. He escaped from Salt Lake City’s Tracy Aviary in 1987 and lived at the lake eating brine shrimp and socialized with swans and gulls. Although Utah residents suggested releasing more flamingos to help keep Pink Floyd company, wildlife biologists said no to these efforts, with the claim that introduction of a non-native species would have detrimental consequences. Pink Floyd was last seen in Idaho in 2005 and specialists claim that he didn’t survive the winter of 2005 and 2006.

Commerce and Economy

Great Sat Lake is an important contributor to Utah’s economy, providing it with $1.3 billion dollars annually, of which $1.1 billion comes from mineral extraction and other industrial works, an estimate $136 million from tourism and $57 million from brine shrimp harvest. Many types of minerals are extracted from the lake, such as sodium chloride (for water softeners), soft lick blocks (for livestock), potassium sulfate (for commercial fertilizers), magnesium-chloride brine (for producing magnesium metal) and chlorine gas (used as a dust suppresant). 14% of the World’s magnesium supply is also produced at Great Salt Lake, on its southwester shore, operated by US Magnesium.  

The harvest of brine shrimp is extremely important; producing 34-45% of the world’s supply. Initially it was sold as commercial fish food and first harvested in the 1950’s. The focus changed in the ‘70’s, when their eggs came into the spotlight (also referred to as cysts) and were sold outside of the US as food for shrimp, prawns and fish. Today brine shrimp is exchanged in East Asia and South America. The amount of cysts is greatly influenced by numerous factors of which the most important is the lake’s salinity. The greatest productivity occurs when the saltiness of the lake is at around 10%.

The Northern arm of the lake contains oil deposits, but due to its poor quality it is not economically feasible to purify or extract. The oil’s existence in the lake has been known for quite some time and efforts for its production began back in 1904.

Effects of the Causeway

Built in the 1950s by the Morrison-Knudsen company for the Southern Pacific Railroad, the causeway running across the lake hosts a railway on which more than 15 trains pass daily. It has a major impact on local industries, since the waterflow is constrained by it. Because of the causeway, there’s a difference in water composition between the northern and southern part of the lake; the former has a higher concentration of salinity in which brine shrimp cannot survive, whilst the latter has a freshwater inlet where they can thrive. The increased salt and mineral content of the northern part is actually ideal for Great Salt Lake Minerals Company, since it can extract from it.

Water Regulation Projects at Great Salt Lake

In the 1930s a project to dam off one-third of Great Salt Lake on the eastern side with the help of dams aimed to make a freshwater reservoir, providing water fit for drinking and irrigation. It only entered the planning stages, when the Fresh Water Project was abandoned.

The freshwater reservoir called Willard Bay was completed in 1964, which was separated, drained and filled by the Weber River and a section of the Great Salt Lake’s Northern Arm. In the 1980’s record-high water levels dominated the lake, causing a significant amount of property damage to locals living on the eastern region. The water even started to erode the base of the Interstate Highway 80. To avoid any further damage, the State of Utah constructed the West Desert Plumbing Project on the western part of the lake, consisting of a pumping station at Hogup Ridge with three pumps and a capacity of moving 95 m3 per second. It also had an inlet and an outlet canal. More than 40 kilometers of dikes and 16 kilometers of access road separated the pumping station and the town of Lakeside.

The project was designed especially to help increase the surface area of the lake, which meant that water evaporation would also amplify. The pumps transported a portion of the water into the New Foundland Evaporation Basin, a 1,300 km2 desert west of Great Salt Lake. The water level of the lake was regulated with the help of a weir in the dike at the southern part of the Newfoundland Mountains, which sometimes restored salty water from the evaporation basin into the main body of water of Great Salt Lake.

By the end of the first year of operation the pumps removed 620,000,000 m3 of water from the lake. The project, however, was shut down in the summer of 1989 because the water levels dropped by 1.8 meters after reaching peak levels in June of 1986 and March of 1987. The Utah Division of Water Resources cites the project with over one-third of that decline. Although the pumps are no longer in use, they are still kept in place in case water levels will rise again at Great Salt Lake.

Fun Facts and Urban Legends

Land art is a pretty common sight in the area. The most famous piece can be found on the northwestern arm of the lake, near Rozel Point, courtesy of Robert Smithson. He created the artwork called Spiral Jetty in 1970, which can only be seen when the lake level drops below 1,280 meters above sea level.

Great Salt Lake and its shores contain a special type of sand, called oolitic sand, known for its rounded and spherical grains made up of a small mineral grain and concentric stratum of calcium carbonate. The shape itself is similar to that of a pearl.

Local legend has it that in 1875 a local entrepreneur called James Wickham released 2 of his wales into the lake with the aim of attracting tourists. The whales disappeared into the lake and have only been seen a handful of times afterwards.

Another legend states that J.H. McNeil with some of his colleagues working at Barnes & Co Salt Works spotted a large monster in 1877. The creature supposedly had the body of a crocodile and the head of a horse. It attacked the men and ran away afterwards. Another monster-like creature was spotted on Antelope Island 30 years prior by “Brother Bainbridge”, which looked like a dolphin. It was referred to as the “North Shore Monster”.

Tourism and Recreation

Great Salt Lake offers a myriad of leisure activities on site, thus it is one of the most popular destination for tourists in the state. The dramatically fluctuating water levels and the incoming pollution from industrial and urban effluents don’t seem to bother visitors. The State Park boasts a spacious campground with plenty of room for tents and RVs. You can also find a gift shop and a visitor’s center here. Besides these humble means of accommodation, the area is also famous for its luxury resorts and spas, dotting the coastline around Great Salt Lake.

Three resorts, all called Saltair have been operated on the lakeshore for over a century. The first one was constructed in 1893 and was destroyed by a fire on the 22nd of April in 1925. The second Saltair was built and expanded in the same place by new investors and constructors, but was also burned down by an arsonist in 1970. The current building was completed in 1981 and serves as a concert venue.

Public launch facilities can be encountered in various parts of the lake. A visitor center is open to tourists at Antelope Island State Park. Due to the fact that the lake’s salty water is corrosive to metal, motorized craft are an uncommon sight. Sailboats, on the other hand, are extremely popular because of the lake’s expansive spread mixed with a bit of wind, which produces some of the best sailing destinations in the world. There’s also an active Yacht Club at the lake, regularly organizing skill and racing events.

Kayaks, canoes and paddleboards are a common site at Great Salt Lake. Swimming is widespread after the summer solstice, when the waters get a bit warmer. The Great Salt Lake Marina, Black Rock and Antelope Island are the best places to pursue this activity.

Bird-watching is a similarly popular pastime and an annual Bird Festival is held each year here. The most ideal places for bird sightings are the Bear River Migratory Bird Refuge, the Great Salt Lake Shorelands Preserve, the Audubon Lee Creek area, Antelope Island and Great Salt Lake Nature Center at Farmington Bay. Wildlife-viewing is best at Antelope Island State Park, where tourists can observe bison, pronghorn antelope, mule deer, foxes, raccoons, coyotes, bobcats, badgers, porcupines and jackrabbits in their natural habitat.

There are many different routes both for road and mountain biking. Scenic roads around the lake can offer you the best view of Great Salt Lake. If you want to work for the best view in the area, hike up to Wasatch Mountain or take the Bonneville Shoreline Trail. R&G Horse and Wagon offer exclusive horseback rides through the historic Antelope Island. The Golden Spike National Historic Site can be found 56 kilometers north of Promontory Point, symbolizing the transcontinental railroad which was finished in 1869.

Great Salt Lake Fish Species