Avista Corporation is an American energy company which generates and transmits electricity and distributes natural gas to residential, commercial, and industrial customers. Approximately 1,550 employees provide electricity, natural gas, and other energy services to 359,000 electric and 320,000 natural gas customers in three western states. The service territory covers 30,000 square miles (78,000 km2) in eastern Washington, northern Idaho, and parts of southern and eastern Oregon, with a population of 1.5 million.