New York Public Library NYPL puts 20,000 Hi-Res Maps Online for free download and use. The NYPL announces the release with following explanation: “We believe these maps have no known US copyright restrictions.”

Anybody with a computer can create an account, log in, and begin warping and tracing maps. Over ten thousand of the collection’s maps are of New York and New Jersey, dating from 1852 to 1922, including property, zoning, and topographic maps. In addition, over one thousand of the maps depict Mid-Atlantic cities from the 16th to the 19th centuries, and over 700 are topographic maps of the Austro-Hungarian Empire between 1877 and 1914.

Find the maps here