Omega (originally, Delerium Tremens) was a former settlement in Nevada County, California, United States, first populated in 1850 by a single miner, J.A. Dixon, working a claim during the California Gold Rush. The town was located 3.25 miles (5.2 km) east-southeast of the present-day unincorporated town of Washington, California. A sister town, Alpha, located at what is now the site of the historical Omega Hydraulic Diggings, was about 1 mi (1.6 km) north of Omega. In the mid 1850s, following the introduction of hydraulic mining operations nearby, the town prospered. Omega had a post office (which operated from 1857 to 1891), and needed to convert a residence into a jail in late 1858.