 Sleeping Bear Dunes National Lakeshore is a United States National Lakeshore located on the " little finger " of the lower peninsula of Michigan in Leelanau and Benzie counties . The park covers a 35 @-@ mile ( 56 km ) stretch of Lake Michigan 's eastern coastline , as well as North and South Manitou Islands . The park was authorized on October 21 , 1970 . 
