Soldotna is a city in the Kenai Peninsula Borough in the U.S. state of Alaska. At the 2020 census, the population was 4,342, up from 4,163 in 2010. It is the seat of the Kenai Peninsula Borough. Soldotna is located in the Southcentral portion of Alaska on the central-western portion of the Kenai Peninsula. The city limits span 7 square miles along the Kenai River, which empties into the Cook Inlet in the nearby city of Kenai.