Part of the island was incorporated as the Town of Chincoteague within Accomack County in 1908; the municipality annexed the remainder of the island in 1989. Automobile traffic could reach the island with the completion of a causeway in 1922. Two devastating fires in that decade caused the establishment of the Chincoteague Fire Department in 1925; the new volunteer company took over the traditional pony penning, and soon had ponies from nearby Assateague Island swim the narrow channel between the two islands as part of that roundup.