The City of Mercer Island is located in King County, Washington. The population is estimated at 22,000. There are seven private schools operating in the City of Mercer Island. Private Schools in Washington are regulated by the Office of Superintendent of Public Instruction. There are 514 private schools in Washington that are on the approved list of the Office of Superintendent of Public Instruction.
An "approved private school" is defined under Washington law as a nonpublic school conducting a program consisting of kindergarten and at least grade one, or a program consisting of any or all of grades one through twelve which has been approved by the state board of education in accordance with the minimum standards for approval. A total of 78,000 students are enrolled in private schools in Washington.