| length_imperial = 111
| length_round = 0
| length_note = 〔 River mile numbers are shown on the map.〕
| watershed_imperial = 4640
| watershed_note = 〔(【引用サイトリンク】url=http://water.usgs.gov/GIS/huc_name.html )〕
| discharge_location = near Elkton, from the mouth
| discharge_round = 0
| discharge_imperial = 7343
| discharge_note =
| discharge_max_imperial = 265000
| discharge_min_imperial = 663
| discharge1_location =
| discharge1_imperial =
| discharge1_note =
| map = Umpquarivermap.jpg
| map_size =
| map_caption = Map of the Umpqua River watershed
| map1 =
| map1_size =
| map1_caption =
| map1_locator = Oregon
| commons =
The Umpqua River ( ) on the Pacific coast of Oregon in the United States is approximately 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 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.
The Native Americans in the Umpqua's watershed consist of several tribes, such as the Umpqua (a band of the Coquille for which the river is named), and the Kalapuya. These tribes witnessed much of the Great Flood of 1862, during which the Umpqua and other rivers rose to levels so high that even the oldest Indians had never seen a greater flood.
The North Umpqua and South Umpqua rivers rise in the Southern Oregon Cascades, and flow generally west for over to join approximately northwest of Roseburg. In modern terminology, the "Umpqua Valley" is sometimes taken to refer to the populated lower reaches of the South Umpqua south of Roseburg, along the route of Interstate 5. The North Umpqua rises from snowmelt and is considered one of the premier summer steelhead streams in the West.
From Roseburg, the Umpqua flows generally northwest through broad farming valleys in the Oregon Coast Range in a serpentine course past the settlement of Umpqua and the city Elkton. At Elkton, it turns to flow west through a narrower canyon past Scottsburg, which is located at the head of tide. It enters Winchester Bay on the Pacific near Reedsport. It receives the Smith River from the north near its estuary on Winchester Bay. The Umpqua River Light protects ships nearing the mouth of the river.
The Umpqua is one of four major rivers in Oregon that start in or east of the Cascade Range and reach the Pacific Ocean. The others are the Rogue River (in Oregon), Klamath River (flowing from Oregon to California) and Columbia River (flowing from British Columbia to Washington and the Pacific between Oregon and Washington).
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』