Rock Island State Park is a state park of Wisconsin located on Rock Island off the tip of the Door Peninsula at the eastern edge of Green Bay and Lake Michigan.

Rock Island is a mostly wooded island off the tip of Wisconsin's Door Peninsula at the mouth of Green Bay, in Door County, Wisconsin. The 974.87-acre (394.5 ha) island is approximately 1.6 miles (2.6 km) long and 1.1 miles (1.8 km) wide. It rises to 65 meters above Lake Michigan, making it the highest in elevation out of all the Potawatomi Islands. It is almost entirely owned by the Wisconsin Department of Natural Resources, which maintains Rock Island State Park. It is the northernmost part of the town of Washington.