Morrow County is a
county in the
U.S. state of
Oregon. As of the
2010 census, the population was 11,173. The
county seat is
Heppner. The county is named for one of its first white settlers, Jackson L. Morrow, who was a member of the state legislature when the county was created. Half of the
Umatilla Chemical Depot, which includes the Umatilla Chemical Agent Disposal Facility, is within the county.