Pendleton is a city in and the county seat of Umatilla County, Oregon, United States. The population was 17,107 at the time of the 2020 census, which includes approximately 1,600 people who are incarcerated at Eastern Oregon Correctional Institution. Pendleton is the smaller of the two principal cities of the Hermiston–Pendleton Micropolitan Statistical Area. This micropolitan area covers Morrow and Umatilla counties and had a combined population of 92,261 at the 2020 census.