Historic Overlay Districts (HO). The purpose of the Historic Overlay Districts is to protect areas of particular historic significance. These areas are the Hudson River National Historic Landmark District, places listed on the National and State Registers of Historic Places, the Estates District Scenic Area of Statewide Significance, the Town of Hyde Park Historic District, and the historic roadside stone walls along U.S. Route 9, Route 9G and in Staatsburg. For informational purposes, the Town Board shall publish and update as needed a current map of the Historic Overlay Districts. This map shall be available for inspection at the offices of the Town Clerk and the Zoning Administrator, and copies of it shall be available at cost from the Town Clerk.