Wasilla is a city in Matanuska-Susitna Borough, United States and the fourth-largest city in Alaska. It is located on the northern point of Cook Inlet in the Matanuska-Susitna Valley of the southcentral part of the state. Wasilla is the largest city in the borough and a part of the Anchorage metropolitan area, which had an estimated population of 398,328 in 2020.