Hermiston is a city in Umatilla County, Oregon, United States, near the junction of I-82 and I-84. U.S. Route 395 also goes through the center of the city. Hermiston is seven miles south of the Columbia River, Lake Wallula, and the McNary Dam. The Umatilla Chemical Depot and the Umatilla Chemical Agent Disposal Facility are five miles west of the city, northeast of the intersection of I-84 and I-82. As of 2006, the estimated population is 15,410 residents. Hermiston is the smaller of the two principal cities of the Pendleton-Hermiston Micropolitan Statistical Area, a micropolitan area that covers Morrow and Umatilla counties and had a combined population of 81,544 at the 2000 census.