Humboldt Sink is an intermittent dry lake bed, approximately 11 mi (18 km) long, and 4 mi (6 km) across, in northwestern Nevada in the United States. The body of water in the sink is known as Humboldt Lake. The sink and its surrounding area was a notorious and dreaded portion of overland travel to California during the westward migrations of the mid-1800s, which were largely undertaken along the California Trail.
Humboldt Sink is located between the West Humboldt Range (to the southeast) and the Trinity Range (to the northwest), on the border between Pershing and Churchill counties, approximately 50 mi (80 km) northeast of Reno. It is fed from the northeast by the 330 mile (530 km) long Humboldt River, the second longest river in the Great Basin of North America (after the Bear River). Interstate 80 passes along the northwest side of the sink.
The sink has no natural outlet. A channel connecting it with the Carson Sink was cut by the Nevada Department of Transportation in 1984 to prevent Interstate 80 and the town of Lovelock from flooding after heavy snowfall in the preceding three years. This channel has been dry since 1986. The sink, along with the Carson Sink, are remnants of the larger prehistoric Lake Lahontan that existed at the end of the last ice age, approximately 13,000 years ago.
The sink is protected as part of the Humboldt Wildlife Management Area. Wetlands in and near the sink such as the Humboldt Salt Marsh provide important nesting, foraging, and resting habitat to large numbers of migratory birds.
The sink has a long history of human habitation. In addition to Lovelock Cave, an outcrop in the West Humboldt Range in which 2000-year-old duck decoys have been found, there is evidence of huts constructed in the bed of Lake Humboldt. Evidence from these important archaeological sites suggests that Native Americans hunted and fished in the Humboldt Sink during wetter climatic periods.