Horse Guard State Park is a one hundred five-acre public recreation area in Avon, Connecticut, managed by the Connecticut Department of Energy and Environmental Protection. Since the state acquired the land in 1964, it has remained largely undeveloped as a simple natural area. Its name honors the First Company Governor's Horse Guards, founded in 1788 and regarded as the oldest active mounted cavalry unit in the United States. A white-blazed trail begins near the Avon Historical Society's Derrin House on West Avon Road and runs one and a half miles out and back to a rocky crag with views south and west over the surrounding landscape.