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 23,683 at the 2020 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.

The Umpqua River on the Pacific coast of Oregon in the United States is approximately 111 miles (179 km) long. One of the principal rivers of the Oregon Coast and known for bass and shad, the river drains an expansive network of valleys in the mountains west of the Cascade Range and south of the Willamette Valley, from which it is separated by the Calapooya Mountains. From its source northeast of Roseburg, the Umpqua flows northwest through the Oregon Coast Range and empties into the Pacific at Winchester Bay. The river and its tributaries flow almost entirely within Douglas County, which encompasses most of the watershed of the river from the Cascades to the coast. The "Hundred Valleys of the Umpqua" form the heart of the timber industry of southern Oregon, generally centered on Roseburg.