Hudson River Historic District - Credit: Wikimedia Commons
The Hudson River Historic District, also known as Hudson River Heritage Historic District, is the largest Federally designated district on the mainland of the contiguous United States.The Nantucket Historic District includes all of the island of Nantucket. Montana's Butte-Anaconda Historic District, the next largest, covers 9,774 acres (15.2 square miles). The Adirondack Park, also in New York, and Alaska's Cape Krusenstern are larger, but are not conventional historic districts. It covers an area of 22,205 acres (34.6 square miles, 89 km²) extending inland roughly a mile (1.6 km) from the east bank of the Hudson River between Staatsburg and Germantown in Dutchess and Columbia counties in the U.S. state of New York. This area includes the riverfront sections of the towns of Clermont, Red Hook, Rhinebeck and part of Hyde Park. This strip includes in their entirety the hamlets of Annandale, Barrytown, Rhinecliff and the village of Tivoli. Bard College and two protected areas, Margaret Lewis Norrie State Park and Tivoli Bays Unique Area, are also within the district. Read more on Wikipedia
Source: en.wikipedia.org