Tule Lake is an intermittent lake covering an area of 13,000 acres (53 km2), 8.0 km (5.0 mi) long and 4.8 km (3.0 mi) across, in northeastern Siskiyou County and northwestern Modoc County in California, along the border with Oregon.

Modoc County is a county in the far northeast corner of the U.S. state of California. Its population is 8,700 as of the 2020 census, down from 9,686 from the 2010 census. This makes it California's third-least populous county. The county seat and only incorporated city is Alturas. Previous county seats include Lake City and Centerville. The county borders Nevada and Oregon.