The Plumb Estate in East Islip, now part of Heckscher State Park, is a site associated with paranormal activity, particularly at the original location of the central building's foundation, according to Long Island Haunted Houses. Visitors have reported feeling watched on nearby trails, and the sound of a horse has been heard even when no horse is present, potentially linked to the 1899 incident where a Mr. Plum shot and killed Alexander Masterton, Jr. before dying himself. Some people feel watched when walking the trails near the original foundation of the estate. The sound of a horse is often reported along the trail, despite no horses being present.