Kelseyville is a census-designated place (CDP) in Lake County, California, United States. Kelseyville is located 6 miles (9.7 km) southeast of Lakeport, at an elevation of 1,384 feet (422 m). The population was 3,353 at the 2010 census, up from 2,928 at the 2000 census.
The community was formerly named Kelsey, Kelsey Creek, Kelsey Town, Peartown, and Uncle Sam. The place was originally called Kelsey Town in honor of Andrew Kelsey, the first European-American settler in Lake County. Andrew Kelsey was killed in 1850 in an uprising against him by a band of Pomo whom Kelsey had enslaved. This episode ended with the Bloody Island Massacre. The place was called Uncle Sam after Mount Uncle Sam (referred to as Mount Konocti). The Uncle Sam post office opened in 1858 and changed its name to Kelseyville in 1882.
Kelseyville was the first white settlement in Lake County. The first blacksmith shop was opened by blacksmith named Benham in 1857.