Did You Know? The Great Salt Lake, From 1847 to Today

Did You Know?

The Great Salt Lake is the largest saltwater lake in the Western Hemisphere — and the largest lake west of the Mississippi River. A few things about it surprise most people:

• Water flows into the Great Salt Lake through rivers and streams, but no water flows out through surface rivers, making it a terminal lake where water only leaves via evaporation.
• Because evaporation is the only way water leaves, minerals and salts that flow in stay behind and concentrate over time, which is why the lake is saltier than the ocean.
• The lake's salinity is not uniform — a rail causeway built across the lake in 1959 separates it into a north arm and a south arm with different salinity levels, since the north arm receives little fresh water.
• The lake has no fish, because its salinity is too high for fish to survive.
• Brine shrimp and brine flies are among the few species that can live in the lake's saltiest waters, and they form the base of the food web that supports millions of migratory birds.
• Every year, ten million birds from 338 different species rely on the lake during migration — which is why it's been designated a Western Hemisphere Shorebird Reserve Network site since 1991.
• The lake's saltiest waters can turn visibly pink — the color comes from halophilic ("salt-loving") bacteria and archaea, the only organisms able to survive in the north arm's extreme salinity.
• Brine shrimp eggs (cysts) harvested from the lake are sold commercially and used worldwide as feed in aquaculture operations.
• The Great Salt Lake is a remnant of prehistoric Lake Bonneville, a much larger lake that covered a significant portion of what is now western Utah during the last Ice Age.
• The lake's surface elevation and area fluctuate significantly year to year and season to season, since it is shallow relative to its surface area — a small change in water level can expose or submerge large areas of lakebed.

A Brief History: From the Pioneers to Today

• When Mormon pioneers arrived in the Salt Lake Valley in 1847, the Great Salt Lake was already a defining feature of the landscape — and the lake's official water-level record, kept by the USGS, dates back to that same year.
• Three rivers — the Bear, Weber, and Jordan — have long fed the lake, but as Utah's population grew, more and more of that water was diverted upstream for farming and, later, cities, before it ever reached the lake.
• The lake naturally rises and falls with wet and dry cycles. On June 3, 1986 (and again in March 1987), it hit its historic recorded high of roughly 4,211.6–4,211.85 feet. Its surface area at that peak is reported differently by different agencies — see the note below.
• In 1959, a rock-fill railroad causeway was completed across the lake, cutting off water exchange between its north arm (Gunnison Bay) and south arm (Gilbert Bay). Gilbert Bay gets nearly all the freshwater inflow, so it's far less salty than Gunnison Bay — which is why the lake's brine shrimp, brine flies, and the birds that eat them are concentrated on the south side.
• Since the 1986 peak, the lake has dropped roughly 22 feet, driven largely by decades of water diversion for agriculture and growing urban use along the Wasatch Front, compounded by drought.
• The lake hit a historic recorded low in November 2022, at 4,188.5 feet — well under a quarter of its 1986 surface area by any agency's measure.
• That drop exposed tens of thousands of acres of lakebed, raising concerns among scientists about dust — some of it containing naturally occurring arsenic and other heavy metals — blowing off the exposed bed toward Wasatch Front communities.
• The lake has partially recovered since then: after two above-average water years, the South Arm reached 4,194.1 feet by July 2024, per FRIENDS of Great Salt Lake — a real improvement, but still about 4 feet below the 4,198'–4,205' range the Great Salt Lake Commissioner's Office has set as its target for a healthy lake.

A note on surface-area figures: elevation readings for the 1986 high and 2022 low are consistent across agencies, but reported surface area for those same benchmarks is not — the State of Utah and NASA report 3,300 sq mi (1986) and ~800 sq mi (2022), while USGS's own Hydro Mapper page reports ~2,300 sq mi (1986, citing a 2002 Utah DNR study) and ~890 sq mi (2022, citing a 2023 USGS data release). Both figures are shown below rather than picked between.

Watch the Lake Shrink

This is a schematic, not a survey — it's built to show the scale of the change, not to stand in for satellite or GIS data. Pick a benchmark year to see roughly how far the shoreline has retreated and what the lake's elevation and surface area were at that point.

Why This History Matters Now

Questions Worth Asking

The people quoted below are all on the public record about the lake. Their own words raise questions worth sitting with — not to catch anyone in a contradiction, but because the answers aren't yet public.

"Restoring Great Salt Lake to health will not be a one-year, one-policy, one-constituency solution. Rather, a coordinated, data-driven approach will be necessary so decision-makers can evaluate tradeoffs and balance competing interests." — Brian Steed, then–Great Salt Lake Commissioner and Great Salt Lake Strike Team Co-Chair, via the Kem C. Gardner Policy Institute. Gov. Cox appointed Hannah Freeze as Commissioner in his place on July 22, 2026.

If a "coordinated, data-driven approach" is the goal, why do the state's own cited sources — greatsaltlake.utah.gov, NASA, and USGS's own Hydro Mapper — still report different surface-area figures for the same two benchmark years, more than three years after the 2022 low? Which figure, if any, is the one policymakers are actually using to evaluate those tradeoffs?

"The Great Salt Lake Watershed Enhancement Trust is helping bring more water to Great Salt Lake and its wetlands, which are crucial for millions of birds that rely on this ecosystem and the health of the surrounding communities." — Tim Brown, President/CEO of Tracy Aviary, Great Salt Lake Watershed Enhancement Trust Council member

The Trust's own materials describe its work in these public terms, but the Trust Council itself operates under bylaws that allow closed meetings and non-disclosed votes. What would it take for the Council's decision-making to be as visible to the public as the state's own Great Salt Lake Advisory Council?

"If we don't have a healthy Salt Lake ecosystem, then it affects military readiness." — Tyler Smith, Installation Resiliency Manager, Utah Department of Veterans & Military Affairs, to the Veterans & Military Affairs Commission, Sept. 2026

The Great Salt Lake Sentinel Landscape program ties lake health directly to military readiness and reports a 2.7-million-acre footprint — but its own 2025 profile lists zero acres protected and zero acres enrolled through fiscal year 2024. What does "protected" or "enrolled" actually mean under this program, and when does the state expect that number to move off zero?

"We have been diverting water for housing and agriculture in the Wasatch Valley for about a century." — Bonnie Baxter, biologist, Westminster College, via NASA Earth Observatory

If a century of diversion is the root cause, does a partial recovery to 4,194.1 feet in 2024 — still four feet below the state's own healthy-range target — represent a real change in that underlying pattern of water use, or mainly the benefit of two unusually wet years?