A useful term to know when ordering from the USGS

The mathematical site Mathworld [1] defines the term quadrangle thus:

In cartography, a quadrangle is typically what the layman would think of as a rectangle, and perhaps is best seen as a rectangle made on the spherical surface of the earth. The [2] Glossary at the UT’s Perry-Castañeda Map collection defines it thus:

The quadrangle, as stated above, is the basis for the mapping program of the U.S. Geologic Survey. This is a public product, and [3] can be purchased at the USGS store. These maps are well-known for their detail and accuracy, and have been guiding outdoorsmen (and women) in the United States for decades.

The most well-known form of this map is the so-called “7.5 Minute Quad”, named such because thier width is 7.5 minutes (where, speaking angularly, 60 minutes equal one degree of longitude). These
maps are at 1:24,000 scale (amounting to 2.64 inches equalling one mile on paper). Acorrding to the USGS, at this scale, more than 54,000 individual maps are required to cover the 48 conterminous Unitied States, Alaska, Hawaii, and US territories.