Whidbey Island is one of nine islands located in Island County, Washington. Whidbey is located about 30 miles north of Seattle, and lies between the Olympic Peninsula and the I-5 corridor of western Washington. Whidbey Island forms the northern boundary of Puget Sound. The major centers on the island are Langley, Freeland, Greenbank, Coupeville, and Oak Harbor. A 2006 real estate survey has estimated the population of Whidbey Island at 59,704.