The USGS developed digital quad grids at 1:24000, 1:100000 and 1:250000. These grids contain the quad reference number and name as maintained in the USGS Index to topographic and other Map Coverage books or Catalog of topographic and other Published Map books. These individual zip files are in an ArcView shapefile format and in the following projection:

projection				Lambert Azimuthal Projection 
units					meters
major axis				6370997.00000
minor axis			              0.00000
radius of the sphere of reference 	6370997.00000
longitude of center of projection     -100 0  0.00000
latitude of center of projection	 45 0 0.00000
false easting 			      0.00000
false northing 			      0.00000