Drain is a city in Douglas County, Oregon, United States. The population was 1,151 at the 2010 census. Drain is named after town founder and politician Charles J. Drain, who donated 60 acres (24 ha) of nearby land to the Oregon and California Railroad in 1871.

Douglas County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 111,201. The county seat is Roseburg. The county is named after Stephen A. Douglas, an American politician who supported Oregon statehood. Douglas County comprises the Roseburg, OR Micropolitan Statistical Area. In regards to area, Douglas County is the largest county west of the Oregon Cascades.