Before extolling the features of these maps, a few definitions are in order.  A quadrangle is a map which is bordered by a set interval of latitudes and longitudes.  In this series, that interval is 7½ minutes (7.5'), which equals ¼ degree.  The result is that quadrangle maps (quads, for short) have no overlap with adjacent quadrangles, and you can cut or fold the margin of one and attach it to an adjacent one with some precision.

Topographic (topo, for short) refers to any highly detailed map showing landforms as well as cultural landmarks.  This series of maps and most other US Geological Survey topographic maps use elevation contours to show the form of the land.  Elevation contours are so often the means of showing the landscape that for many people, contour maps are synonymous with topographic maps.  But, contrary to this belief, a map can still be topographic and not use contours.

Elevation contours are lines, depicted in brown on USGS maps, that connect points of equal elevation.  They are usually provided at standard intervals, such as 20 feet or 40 feet increments of elevation.  The closer together the elevation contours, the steeper the slope; areas with few or no contours on a contour map are nearly (if not exactly) level.

The maps in this series are produced at a scale of 1:24,000.  That ratio means that any one unit on the map equals 24,000 of those units in the landscape it represents.  So one inch on the map equals 24,000 inches, which equals 2,000 feet, which in turn equals 0.378 miles (a little less than 4/10 of a mile).  Compare that to your average western state road map, which often have a scale in the ballpark of 1:1,000,000.  The 1:24,000-scale topographic maps have roughly 42 times the detail of most western state road maps!

In addition to elevation contours, these topo maps typically show rivers, creeks, washes, and other watercourses; woodlands; benchmarks; township and section lines; major power lines; roads of all classes, including highways, city streets, graded dirt roads and jeep trails; hiking trails; lakes, ponds, tanks, springs, and marshes; water towers, individual buildings (with special symbols for landmark buildings such as schools and churches), radio/TV antennas; fire lookouts, campgrounds, picnic areas; airports, landing strips, and railways; mines, quarries, borrow pits, tailings; boundaries of states, counties, incorporated cities, parks, preserves, forests, reservations, military bases, and other political subdivisions; and more.  Click on the map images above left to see a sample of part of a USGS quad.

With that kind of detail, USGS 7.5 minute topo maps are particularly popular with hikers, mountain bikers, equestrians, hunters, scientists, utility planners, realtors, rural property owners, and many other user groups.

There are tens of thousands of different quads in this series alone, and USGS has a limited budget for revisions.  It is not surprising, then, that few of these maps are up-to-date.  In fact, even a newly published USGS quad may have had a survey date two years before, and an editing date the year before it was printed.  It is quite common for the most recent quad for an area to be three decades old.  Many of the current quads for the parts of Arizona we stock were made in the 1960s and 1970s.  There are only a few with publication dates in the 1990s and 2000s.  Not to worry—most people buy these for their portrayal of the landscape; the mountains, drainages, springs, and other features rarely change, and in rural areas, even the roads don't change all that much.  You might wonder about the reliability of a five or ten year old highway map, but for a USGS quad, only five to ten years old is hot off the press!  Our listings for the USGS titles we stock include the publication date—a feature that many other dealers omit.