Umatilla is a city in Umatilla County, Oregon, United States. The population in 2010 was 6,906, but the city's population includes approximately 2,000 inmates incarcerated at Two Rivers Correctional Institution. Umatilla is part of the Hermiston-Pendleton Micropolitan Statistical Area, but has the highest poverty rate and lowest Median Household Income, of all communities in the area; trailing neighboring Hermiston in household income by nearly 23%.