|Location||Lane County, Oregon,
|Primary inflows||Row River|
|Primary outflows||Row River|
|Catchment area||265 sq mi (690 km2)|
|Basin countries||United States|
|Surface area||1,840 acres (740 ha)|
|Average depth||42 ft (13 m)|
|Max. depth||97 ft (30 m)|
|Water volume||77,600 acre·ft (95,700 dam3)|
|Residence time||1.7 months|
|Shore length1||13 mi (21 km)|
|Surface elevation||835 ft (255 m)|
|1 Shore length is not a well-defined measure.|
Set at the south end of the Willamette Valley and criss-crossed by the Coast Fork Willamette River and its tributary the Row River, the area was susceptible to periodic flooding from large rains and snow melts in the surrounding mountains prior to the construction of the dam.
In the 1940s the United States Army Corps of Engineers began construction of dams which created the Cottage Grove Reservoir and Dorena Lake. Dorena Lake has become an enormously popular summer vacation destination with its Baker Bay Marina and camping and Shwartz Park campground. Visitor estimates top 80,000 people annually.