Fox River is located on the western side of the Kenai Peninsula at (59.847372, -150.926178). It is at the head of Kachemak Bay, where the Fox River enters it. The CDP extends north from the bay to high ground north of Caribou Lake. It is bordered to the southwest by Falls Creek, which separates the community from the Fritz Creek CDP. Most of the current population of Fox River is in the southwest part of the CDP, on high ground overlooking Falls Creek, Swift Creek, and Moose Creek.