A prominent feature in Lake Entiat is the 150-acre Turtle Rock Island, located northeast of Lincoln Rock State Park. Originally part of the mainland on the south bank of the Columbia, this rocky outcrop became an island when the lake formed.[2]U.S. Highway 2 formerly ran through the area that became the island, and remnants of the road may still be seen in aerial photos. The island is now a nature preserve and fish hatchery, with access only by boat.[3]