In collaboration with the US Geological Survey (USGS), we recently updated Esri’s online USGS historical topographic map collection with over 1,745 new maps, bringing the total number of maps in our collection to over 181,000 (181,008 to be exact). We also corrected a number of maps that our users reported as having georeferencing or other errors. These maps are part of the USGS Historical Topographic Map Collection (HTMC) which includes all the historical topographic quadrangle maps (quads) tha...