Resource - USGS Historical Topographic Maps

Thanks for this gem from Greg Miller at Wired -

The USGS has a new online map viewer that display maps that cover the entire country and are FREE to download.   Here's from Greg -

"Hunting for historical topo maps on the USGS site used to be confusing and annoying. It involved a lot of clicking on what you hoped was the right thing, squinting at the tiny preview maps, and twiddling your thumbs while the enormous full-sized version downloaded. And then starting over when it turned out to be the wrong thing....Now, browsing and searching for maps is much more intuitive. You can type or zoom in on a particular place, limit your search to maps of a particular scale or from a particular range of dates. You can download them in a variety of formats, from JPGs (fine for printing out a nice map to put on your wall), to KMZ files (to import into Google Earth), to GeoTIFFs (for the power users who wants to import maps into GIS software). There’s even a YouTube tutorial that teaches you some handy tricks (pro tip: hold the shift key and drag the mouse to highlight an area to zoom in on)."

All this thanks to USGS employee Chris Garrity.  Check it out at USGS Historical Topographical Maps
From the website - 

Accessing Historical Topographic Maps Has Never Been Easier

TopoView highlights one of the USGS's most important and useful products, the topographic map. In 1879, the USGS began to map the Nation's topography. This mapping was done at different levels of detail, in order to support various land use and other purposes. As the years passed, the USGS produced new map versions of each area. The most current maps are available from The National Map. TopoView shows the many and varied older maps of each area, and so is useful for historical purposes—for example, the names of some natural and cultural features have changed over time, and the 'old' names can be found on these historical topographic maps.

This interface was created by the National Geologic Map Database project (NGMDB), in support of topographic mapping program managed by the National Geospatial Program (NGP). Geologic mapping and topographic mapping at the USGS have a long tradition together (see 1888 report). The NGMDB project is proud to assist the NGP in bringing these maps to the Web.

Packed With New Features And Downloadable File Formats

The maps shown through topoView are from the USGS’s Historical Topographic Map Collection (HTMC). The goal of this scanning, which started in 2011, is to provide a digital repository of USGS 1:250,000 scale and larger (more detailed) maps printed between 1884 (the inception of the topographic mapping program), and 2006. Currently, there are more than 178,000 maps in the HTMC. The NGP is accurately cataloging and creating metadata to accompany high-resolution, georeferenced digital files of each of these printed maps. At present, these maps are offered as GeoPDFs, through The National Map and the USGS Store. However, additional formats are now being offered for evaluation and use through topoView to include:

• GeoTIFF – The GeoTIFF files are a compressed, 300 dpi TIFF image format, with embedded georeferencing information so that the map can be used directly in a Geographic Information System (GIS). The GeoTIFFs are generated at true scale, allowing users to plot the map at the intended map scale in cases where a hard copy is needed.
• JPEG – The high-resolution JPEGs, or 'Browse JPEG' format are useful for getting a quick view of the map in order to find place names or simply explore the map area without the need for downloading a large file.
• KMZ – The KMZ format is a compressed form of the KML format which is used for displaying the maps in Google Earth.