Lake Abert, Saline lake in Lake County, Oregon.

Lake Abert is a shallow alkali lake in Lake County, Oregon, about 15 miles (24 km) long and 7 miles (11 km) wide at its northern end, narrowing to roughly 1 mile (1.6 km) at the south. It covers about 57 square miles (150 km2) but reaches only 11 feet (3.4 m) at its deepest, averaging 7 feet (2.1 m). Its elongated triangular basin lies below Abert Rim, a steep escarpment rising over 2,500 feet (760 m) above the water, with Coglan Buttes to the west and the Coleman Hills to the north.

John Work of the Hudson's Bay Company made the first written record of the lake on 16 October 1832, calling it Salt Lake. In 1843 John C. Fremont named it after Colonel John James Abert, chief of the Army Corps of Topographical Engineers, while mapping from The Dalles to Sutter's Fort. The lake is a remnant of Pleistocene Lake Chewaucan, which dried up at the end of the epoch.

The Northern Paiute called the lake tɨbaizɨ naʔa panɨnadɨ, meaning "bad/unpotable water." Stone house rings along the east shore, numerous there and not found elsewhere in the Great Basin, mark prehistoric occupation. Paisley Caves excavations by Luther Cressman in the late 1930s and Dennis Jenkins from 2002 yielded evidence of human presence up to 14,300 years ago.

There are no developed campgrounds at Lake Abert, and swimming or prolonged contact with the water can harm humans because of its extreme alkalinity. The main activity is birdwatching, especially during migration. The Bureau of Land Management manages the lake and surrounding land, including a 6,886-acre grazing allotment along the southwest shore.

The water is home to unusual small organisms that can survive in few other places, including tiny crustaceans and specialized insects. These creatures are adapted to the extreme salinity and form a food source for millions of migratory birds that pass through each year.