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.Morrow County is part of the Pendleton - Hermiston, OR, Micropolitan Statistical Area. It is located on the south side of the Columbia River and is included in the eight-county definition of Eastern Oregon.HistoryMorrow County was created in 1885 from the western portion of Umatilla County and a small portion of eastern Wasco County. It is named for Jackson L. Morrow, a state representative who advocated for the county's formation. Heppner was designated the temporary county seat at the time the county was created and narrowly defeated Lexington in the election held in 1887 to determine the permanent county seat.
