USGS Topographical Maps

Charles A. Reeves, Jr.


Many of us who have done genealogical research quickly became familiar with what most call "topo maps." These are maps the U.S. Geological Survey (USGS) first started publishing in 1884.  The goal was to create a series of maps of the entire United States based on a grid defined by the latitude-longitude (Lat/Long) coordinate system used for many, many years to pinpoint locations on the earth.  Since the advent of the Global Positioning System (GPS) satellites, most folks now call these GPS coordinates. Following is information on what maps are available, how to obtain and use them, and how to use the associated USGS Geographic Names Information System (GNIS).

The maps are useful in genealogical research because of the amount of information they contain. The USGS lists approximately 65 different kinds of things shown on the maps, which they call "Feature Class." These include: Airport, Bend, Bridge, Building, Canal, Cave, Cemetery, Church, Dam, Falls, Forest, Gap, Harbor, Hospital, Island, Lake, Locales, Military, Mine, Populated Place, Post Office, Range, Ridge, School, Spring, Stream, Summit, Swamp, Tower, Trail, Tunnel, and Valley, just to name a few (well, maybe not a few. . .). These names will be important when I discuss GNIS. The USGS has scanned every map they ever produced, and digital copies are available for download on-line, as well as new versions as they are produced.

Some may be wondering why, in this era of instant gratification, one would ever be interested in topo maps when most of us carry a phone or tablet where maps can be easily viewed. Those maps certainly have their place, and can show a substantial amount of information, but they sometimes don't contain the historical information needed in genealogical research.

A note about Soil Maps: I see these old maps come up on eBay all the time. I don't doubt they might be useful for some, but not for those doing genealogical research. They show very little detail.

The Early Maps

As stated, the USGS started publishing topo maps in 1884. This lasted until around the 1920s or 30s, when this project was terminated without being finished; some (perhaps many) of the planned maps were never completed.  These early maps covered 30 degrees of Latitude and Longitude.* They are sometimes called by their scale, 1:125,000, meaning that one foot on the map represents 125,000 feet on the ground. They typically cover approximately 28 miles east-west (longitude) and 38 miles north-south (latitude).

*Latitude and Longitude are measured in degrees, minutes and seconds, and just like time measurement, there are 60 seconds in a minute and 60 minutes in a degree. Latitude and Longitude are also frequently displayed as decimal degrees; e.g., 60.123456 (it can take a lot of decimal places to achieve the accuracy needed to locate something). Regardless, there is a connection between Lat/Long and time which we won't delve into here. For those interested, Dava Sobel wrote a really good book, since made into a TV movie, "Longitude," about the quest for a timepiece good enough to establish Longitude with enough precision so that voyagers, primarily those navigating sailing ships, would know where they were.

I've never found and index showing what early maps the USGS actually published, but I have determined those that exist for East Tennessee. These are shown in the figure below.  A PDF version is also available.  More later on how to obtain copies of these maps, where the names of the maps will be needed.

 Later Maps

Around the early 1930s the USGS came up with a new grid system for the U.S. based on maps covering 7.5 degrees Lat/Long. These maps are the ones most of us are familiar with today. They also published 30x60 minute, 1:100,000 scale maps, and 1x2 degree, 1:500,000 maps and others, but those will not be discussed here.  The 7.5 degree maps are also called 1:24,000, meaning that one foot on the map represents 24,000 feet on the ground. So they have over five times the resolution of the 30 minute maps, thus showing much greater detail, which is probably the reason the USGS decided to go this route. These maps cover approximately 10 miles east-west, and 13 miles north-south.

Grid maps showing maps covering each state in the U.S. are available, although I've only seen the ones for Tennessee and Kentucky. They cannot be shown here because of their size; e.g., it takes almost 1000 topo maps to completely cover Tennessee.  But a PDF version is available.  As for the early maps, the names of the maps will be needed if you want to download copies. A copy of the USGS brochure is also available that explains what all the symbols, etc. on the maps mean, "Topographic Map Symbols."

I do have an index map for the Smoky Mountain area, shown below.  A PDF version is also available.

How to Obtain the USGS Maps

As mentioned earlier, the USGS has scanned every topo map they have produced. These are available on-line at the site below:

Loads of information is available on this site, but of most interest here is downloading images of the topo maps.  The one I normally use is the text query application:

  • On this page first select the State from the drop down list; e.g., Tennessee.
  • If you want to see all the maps available for a given map name, leave the Scale set to -All scales-.
  • Enter a Map Name in the next box.  This is where you will either need the early index above or the 7.5 minute index. For example, enter Knoxville.
  • For Map Type, leave it set on the default "All" to see all maps available.
  • Then click on the Search button.
For the Knoxville example the list that comes up shows that the USGS published 1:24,000, 1:48,000, 1:125000, and 1:250,000 scale maps with the name Knoxville. The ones of most interest to those doing genealogical research are the early 30 minute (1:125,000) ones (1892-1901) and the early 7.5 minute (1:24,000) ones starting in 1935. Perhaps obvious, but the early ones will show the area before the dams were built.

To download an image of a map, click on the appropriate box in the "Download GeoPDF". Warning: These images are large; e.g., 30-40 MB. So don't try to download them unless you have a high speed connection or a lot of time. It is also faster if you do this at night and weekends. They are zip files, so you would think they would be even larger on your computer when you un-zip them, but they aren't.

An aside for the techie types: These are georeferenced images, so they can be used with GIS software. They can also be opened in software like Adobe Illustrator and all layers will be there. Some of the later versions even have aerial photos as background (so they can be a source for aerial photos), although the USGS seems to have abandoned this in recent versions.  I think the photos made the maps hard to read, and sometimes masked  features.

Feel free to explore. You might find it easier to use the National Map Viewer on the first link above, but when I tried it just now (2/4/16), I got a note that they were migrating to a new system. I'm not that familiar with this method, but at first glance it would seem that you don't need to know the map name(s) to download them.

So what to do with the images once you get them?  You can certainly look at them on your computer screen or handheld device. You can also get them printed at places like FedEx Office (formerly Kinko's). They are typically 22" wide by 27" high, but can be printed slightly smaller and are still readable; e.g., 16" x 20".

The USGS Geographical Information System (GNIS)

GNIS is a searchable database containing every feature named on all the USGS topo maps. My first usage was to search for cemeteries and churches when doing research on my family history. I still use it quite often. It's also a good way to determine which maps you need to look at, since it identifies the maps on which the features appear. The only downside is that it only includes names that appear on current maps, although the last time I checked, some labeled as "historical" were also listed, frequently without locations (other than the county they were in).

Prior to learning about GNIS, my main source for this kind of information was a book produced in 1974 by the State of Tennessee, Department of Conservation, Geology Division, "Place Names of Tennessee," by Ralph G. Fullerton. It lists feature names for each county and the map they appear on. Each county listing also includes a little map showing which topo maps cover the county.  As of this writing, I found three copies on abebooks.  I am not aware of such books for other states.

You access GNIS from this link:

You normally start by entering the name of what you are looking for in the Feature Name box. It is sometimes better if you don't enter the entire name; e.g., if you're looking for "Homesick Mountain," just enter "Homesick" (without the quotes).  You will get a listing of everything with Homesick in its name, which sometimes turns up some unexpected surprises.

But you don't have to enter anything into the Feature Name box. You can instead  pick something from the Feature Class list (although you can certainly do both).  More about this below.

Be sure to either enter something in the Feature Name box or pick from the Feature Class list.

Next pick a state from that pop-down list. You must select a state; GNIS will not proceed without one. The reason is probably obvious. If you don't, GNIS would have to search the entire U.S., which would probably overload GNIS and shut it down.

Lastly, most often you will want to select a county from that pop-down list. You should always pick a county if you are searching by Feature Class with nothing in the Feature Name box.

To illustrate the Feature Class search: If you want to find all the cemeteries shown on the topo maps in a particular county, just leave the Feature Name box empty and pick Cemetery from the Feature Class. But be forewarned that these kinds of searches can take a few minutes. For example, if you want to find all the cemeteries in Jackson County, Tennessee, pick Cemetery, Jackson County, and Tennessee. You will get you a list of 34 cemeteries that are named on the topo maps for Jackson County.

This illustrates a problem with the GNIS search, since it only lists the cemeteries that have names. There are a lot of un-named cemeteries shown on the topo maps. And for most, if not all, counties, there are a lot of cemeteries that don't even appear on the maps, such as small family cemeteries.

At this point you can click on "View & Print all" to see the entire list, and/or click on "Save as pipe '|' delimited file. For the latter, the file is saved as a .csv file with a "|" separating the fields. Any text editor can open it, although programs like Microsoft Excel handle it better.

Good Hunting!

Return to the TNGenWeb Maps page.

This page first created 05 February 2016.