In the 1930s, dredge spoils from the Chesapeake Bay were used to create 29 islands from Coffin's Point to Tingle's Island. Because of erosion, only four of the thirteen islands designated for wildlife protection in 1964 remain. Heron and Skimmer Islands, located north of the U.S. Route 50 bridge, were added to the Sinepuxent Bay WMA in 1993. These islands, totaling 25 acres (100,000 m2), are a mixture of marsh and tidal mud flats.