Baker City is a city in and the county seat of Baker County, Oregon, United States. It was named after Edward D. Baker, the only U.S. Senator ever killed in military combat. The population was 9,828 at the time of the 2010 census.

This is a complete List of National Historic Landmarks in Oregon. The United States National Historic Landmark (NHL) program is operated under the auspices of the National Park Service, and recognizes buildings, structures, districts, objects, and similar resources nationwide according to a list of criteria of national significance. The state of Oregon is home to 17 of these landmarks, two of which extend beyond Oregon's borders into other states, as well as one site from which NHL status was withdrawn upon its destruction.

Pendleton is a city and the county seat of Umatilla County, Oregon. 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.

Walla Walla is the largest city and county seat of Walla Walla County, Washington, United States. It had a population of 31,731 at the 2010 census, estimated to have increased to 32,900 as of 2019. The population of the city and its two suburbs, the town of College Place and unincorporated Walla Walla East, is about 45,000.Walla Walla is in the southeastern region of Washington, approximately four hours away from Portland, Oregon, and four and half hours from Seattle. It is located only 6 mi (10 km) north of the Oregon border.