High Quality Content by WIKIPEDIA articles! The King County Sheriff`s Office (KCSO) is a local police agency in King County, Washington. It is the primary law enforcement agency for all unincorporated areas of King County, as well as 12 cities, and 2 transit agencies, which contract their police services to the KCSO. KCSO also provided Police and Fire ARFF Services to the King County International Airport (Boeing Field. KCSO also provides regional-level support services to other local law enforcement agencies such as air support and search and rescue. The department has over 1,000 employees and serves over 1.6 million citizens, over 500,000 of whom live in either unincorporated areas or the 12 contract cities.