Pacific County is a county in the U.S. state of Washington. As of the 2020 census, the population was 23,365. Its county seat is South Bend, and its largest city is Raymond. The county was formed by the government of Oregon Territory in February 1851 and is named for the Pacific Ocean.

Lewis County is a county in the U.S. state of Washington. As of the 2020 census, the county's population was 82,149. The county seat is Chehalis, and its largest city is Centralia. Lewis County comprises the Centralia, WA Micropolitan Statistical Area, which is also included in the Seattle-Tacoma, WA Combined Statistical Area.