Mid-Columbia Libraries is a library system in Eastern Washington. There were 270,125 people in its service area in 2023, which spans the Tri-Cities metropolitan area except for Richland, which retains a city library: West Richland, Kennewick, and Pasco, and surrounding Benton, Franklin, and parts of Adams Counties are part of Mid-Columbia. It was founded in 1948, originally to serve patrons in unincorporated parts of the counties.