Mount Vernon is a city in Grant County, Oregon, United States. Its post office was established in 1877 and named after a black stallion that belonged to settler David W. Jenkins. The stallion's stable

Grant County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 7,233, making it Oregon's fourth-least populous county. The county seat is Canyon City. It