|Location||Oregon Coast, Douglas and Coos counties|
|Primary inflows||Clear, Eel, and Marsh creeks|
|Primary outflows||Eel Creek|
|Catchment area||10 square miles (26 km2)|
|Basin countries||United States|
|Surface area||355 acres (144 ha)|
|Average depth||34 feet (10 m)|
|Max. depth||65 feet (20 m)|
|Water volume||12,200 acre feet (15,000,000 m3)|
|Residence time||6 months|
|Shore length1||11.5 miles (18.5 km)|
|Surface elevation||66 feet (20 m)|
|1 Shore length is not a well-defined measure.|
Eel Lake is large, deep lake in a chain of water bodies along the Oregon Coast south of the Umpqua River in the United States. The chain includes other large lakes—Clear, North Tenmile, and Tenmile—as well as smaller lakes, which drain into the Pacific Ocean via Tenmile Creek.
Eel Lake is about 7 miles (11 km) south of Reedsport, east of U.S. Route 101 and north of Lakeside. Steep slopes of the Oregon Coast Range border Eel Lake on the east. William M. Tugman State Park borders the lake on the west, and Oregon Dunes National Recreation Area is less than 1 mile (1.6 km) further west.
Clear Lake, to the north, drains into the west side of Eel Lake via Clear Creek as do the smaller lakes Edna, Teal, Stuttpelz, and Hall. Water exits Eel Lake via Eel Creek, a tributary of Tenmile Creek. Eel Lake is the source of drinking water for about 1,200 people in and near Lakeside.
The lakes in the Tenmile Creek watershed formed after rising sea levels, driven by post-glacial warming, inundated the lower reaches of the creek and its tributaries. Sand dunes that later formed along the coast altered the region's drainage patterns and led to a string of lakes at varied elevations within the Tenmile basin.
William M. Tugman State Park surrounds the western arm of Eel Lake. It has 94 campsites for recreational vehicles (RVs) as well as 16 yurts for hikers and bikers; a day-use area, a boat ramp, a fishing dock, and a hiking trail. Activities on or near the lake include fishing, swimming, boating, and wildlife watching. The lake supports populations of largemouth bass, crappie, stocked rainbow trout, steelhead (sea-run rainbow trout), and Coho salmon, the latter of which must be released if caught.
- Johnson, Daniel M.; Petersen, Richard R.; Lycan, D. Richard; Sweet, James W.; Neuhaus, Mark E., and Schaedel, Andrew L. (1985). Atlas of Oregon Lakes. Corvallis: Oregon State University Press. p. 191. ISBN 0-87071-343-4.
- "Eel Lake". Geographic Names Information System. United States Geological Survey. November 28, 1980. Retrieved January 1, 2013.
- "Atlas of Oregon Lakes: Eel Lake (Coos County, Douglas County)". Portland State University. 1985–2012. Retrieved January 1, 2013.
- "William M. Tugman State Park". Oregon Parks and Recreation Department. Retrieved January 1, 2013.