Lexington is a town in Morrow County, Oregon, United States. The population was 238 at the 2010 census. It is part of the Pendleton–H…Lexington is a town in Morrow County, Oregon, United States. The population was 238 at the 2010 census. It is part of the Pendleton–Hermiston Micropolitan Statistical Area. Lexington was named by early settler William Penland for his hometown of Lexington, Kentucky. Lexington post office was established in 1885. In 1886, shortly after Morrow County was created, Lexington lost by 33 votes to Heppner in an election to determine the county seat. The town was incorporated in 1903, and had a population of 185 at the 1910 census.