It's Michigan!

Besides being the automobile capitol of the world, Michigan has 3,288 miles of coastline - the longest freshwater coastline in the United States and second only to Alaska in total miles of coastline. Michigan is loaded with lakes, sandy beaches, quaint lighthouses, majestic waterfalls and even historic shipwrecks. Its name comes from the Ojibwe word mishigami, meaning "large water" or "large lake."