The Rock Island II Site is an archaeological site located on the south side of Rock Island, in Door County, Wisconsin, United States, at the mouth of Green Bay, within the boundaries of Rock Island State Park. It is classified as an Early Historic site with occupations by the Potawatomi, Huron, Petun, Ottawa and Wyandot tribes. It was listed on the National Register of Historic Places in 1972, and was designated a National Historic Landmark in 2023. It is one of the best-preserved sites documenting early Native-European contacts in the Great Lakes region.