Historical records of moose (Alces alces) in Washington are limited to the northeastern corner of the state. There are no paleozoological records of moose in Washington. Since the beginning of the third millennium, moose have been occasionally reported in southeastern Washington. A sub-adult bull moose was photographed in southeastern Washington in July 2009, about 80 km west of the nearest historically documented occurrence of moose. The observed individual and other recent sightings in southeastern Washington are likely the result of an increasing population of Idaho moose and their expansion into western areas of that state and eastern Washington.