Great Salt Lake

The Great Salt Lake in northern Utah is the largest saltwater lake in the Western Hemisphere and the largest natural lake west of the Mississippi River, covering roughly 1,700 square miles at historical average levels. The lake sits at approximately 4,200 feet elevation in the Great Basin, flanked by the Wasatch Mountains to the east and vast salt flats to the west. It is the remnant of prehistoric Lake Bonneville, which covered much of the region during the last ice age. Salinity varies dramatically across the lake: the south arm (where freshwater tributaries enter) ranges from 5 to 14 percent salt content, while the hypersaline north arm (isolated by a railroad causeway) reaches 27 percent and appears visibly pink from halophilic bacteria that thrive at extreme salinity. Antelope Island State Park, 35 miles northwest of Salt Lake City via a 7-mile causeway, provides the most accessible shore access, including Bridger Bay Beach where visitors can wade and float in the water's extreme buoyancy. The lake is a globally critical habitat: up to 80 percent of certain North American shorebird species stage on its shores during spring and fall migrations. American avocet, Wilson's phalarope, eared grebe, snowy plover, and black-necked stilt gather in concentrations numbering in the millions. Brine shrimp and brine flies that thrive in the hypersaline environment form the base of this food chain. Great Salt Lake State Park, 16 miles northwest of Salt Lake City via I-80, offers a boat launch, picnicking, and walking access to the south shore. The lake has declined significantly since the 19th century due to upstream water diversions; its long-term health is the subject of ongoing conservation legislation in Utah.