The Coquille River is a stream, about 36 miles (58 km) long, in southwestern Oregon in the United States. It drains a mountainous area of 1,059 square miles (2,740 km2) of the Southern Oregon Coast Range into the Pacific Ocean. Its watershed is between that of the Coos River to the north and the Rogue River to the south.

The Southern Oregon Coast Range is the southernmost section of the Oregon Coast Range, in the Pacific Coast Ranges, located in the southwest portion of the state of Oregon, United States, roughly between the Umpqua River and the middle fork of the Coquille River, beyond which are the Klamath Mountains. To the east is the Umpqua Valley and to the west the Pacific Ocean. This approximately 55-mile (89 km)-long mountain range contains mountains as high as 3,547 feet (1,081 m) for Bone Mountain. The mountains are known locally in the Roseburg area as the Callahan Mountains, or simply as The Callahans.