Island Park is a city in Fremont County, Idaho, United States. The city's population was 215 at the 2000 census. The city was incorporated by owners of the many lodges and resorts along U.S. Route 20 in 1947 to circumvent Idaho’s liquor laws that prohibited the sale of liquor outside of city limits. It is only 500 feet wide in most locations and, at 33 miles, claims to have the longest “Main Street” in the world. Island Park News is the community's newspaper. Henry's Fork Country is the recreation guide. Island Park apartments for rent comparison page shows most up to date rent information on Island Park apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.