Illinois Beach State Park occupies more than six miles of Lake Michigan shoreline in northeastern Illinois across two units totaling 4,160 acres. Formed from lands acquired beginning in 1948, it includes a northern section once used as Camp Logan, which served as an Illinois National Guard training site and, during the Civil War, a Union prisoner-of-war camp. The park preserves an unusually diverse mix of dunes, wetlands, prairie, and black oak savanna within a wetland of international importance, while also supporting recreation. Though long valued as one of Illinois’s most important protected lakefront areas, its fragile shoreline has faced severe erosion, prompting breakwater construction and gradual rebuilding by 2024.