Judsonville was a city in eastern Contra Costa County, California. It was located 3 miles (4.8 km) northeast of Stewartville, which is now a ghost town. It was a mining town for the nearby coal mines. A post office operated at Judsonville from 1878 to 1883, with a closure in 1879. The name is in honor of Egbert Judson, part owner of a mine.