Are USGS Topo maps always accurate?
USGS Maps are drawn to a published accuracy standard, and personally I have found them to be very accurate. However, the disclaimer is that when used for hiking or hunting they are only as good as we (emphasize we) users. You have to study them and the terrain, be able to properly use a compass and if practiced, use a GPS to plot your postion on the topo since all GPS units will display latitude and longitude which are scaled on the maps. One note, you should not depend on a print of a scanned DRG topo to provide accurate scaling, generally they are fairly close along the latitude (east to west) lines, but will be less accurate along the latitude lines (south to north). And if all else fails, be able to dead reckon a walkout by using the sun, stars and moon positions.