Churchill, county, west-central Nevada, U.S. An original Nevada county, Churchill was created in 1861. The county seat, Fallon, is about 60 miles (100 km) east of Reno. The Carson-Truckee Project (completed 1903) and Lahontan Dam (completed 1914), built on the Walker, Truckee, and Carson rivers, provided the reclamation and irrigation that changed much of the county from a desert into a major agricultural area, producing various crops, poultry, and honey. Area 4,929 square miles (12,767 square km). Pop. (2000) 23,982; (2010) 24,877.