WEST BAY. West Bay is the body of water west of Galveston Island centered at 29°16' N, 94°57' W. Entry to the bay is gained through Galveston Bay on the north and San Luis Pass on the south. The county line between Galveston and Brazoria counties passes diagonally through the bay. Chocolate Bay is a major extension of West Bay to the northwest. The causeway supporting the highway and railroad that connect Galveston Island to the mainland separates West Bay from Galveston Bay.