Eagle River is a community within the Municipality of Anchorage situated on the Eagle River for which it is named, between Joint Base Elmendorf-Richardson and Chugach State Park in the Chugach Mountains. Its ZIP code is 99577. If Eagle River were not part of the Municipality of Anchorage, it would be classified as one of the five largest cities in Alaska.
The name Eagle River was first reported in 1939 by the U.S. Geological Survey. The Eagle River/Chugiak area was settled by homesteaders and prospered on agricultural activities. The Eagle River post office was established in 1961.
In spite of some local opposition, both Chugiak and Eagle River became annexed to the Municipality of Anchorage, when the City of Anchorage and the Greater Anchorage Area Borough were unified in 1975. Efforts to secede from the Municipality surfaced around 2000, but are no longer prominent as the community has seen an influx of individuals who have social and economic ties to Anchorage and the nearby Joint Base Elmendorf–Richardson.
Neighborhoods along the Glenn Highway and Old Glenn Highway corridor are level or sloping, rising towards the Chugach Mountains east of the Old Glenn Highway. The remainder of the community lies along the canyon of the Eagle River; some neighborhoods built in the late 20th century and early 21st century near the Briggs Bridge are built very close to the bottom of the canyon. Neighborhoods along the northern portions of Eagle River, plus Hiland Road and Eagle River Road east of the curve where the road leaves the section line and descends into the canyon, mainly consist of houses built across the mountainsides. Wallace Mountain, on the far northeast corner of the community's road system, is home to several radio station transmitters and towers at the 1,900 feet (580 m) level.