Roseburg is a city in the U.S. state of Oregon. It is in the Umpqua River Valley in southern Oregon and is the county seat and most populous city of Douglas County. Founded in 1851, the population was 21,181 at the 2010 census, making it the principal city of the Roseburg, Oregon Micropolitan Statistical Area. The community developed along both sides of the South Umpqua River and is traversed by Interstate 5. Traditionally a lumber industry town, Roseburg was the original home of Roseburg Forest Products, which is now based in nearby Springfield.