soldotna started out as a clearing in preparation for the construction of the kenai river bridge in 1947. the construction of the sterling highway provided a link to soldotna from the rest of the world and its first post office was built in 1949. in 1957, oil was discovered in the swanson river, which brought an economic boom to the area and in 1960, soldotna was incorporated as a city. in 1964, the kenai peninsula borough was formed and soldotna was included into the borough's formation. the population increased from the 1960s to the 1990s because of its location in between two major highways as well as the development of the oil industry along the kenai peninsula.