Installation Research Tips

Copyright 2000-2014, Scott D. Murdock

Here is some information to assist with the study of Army Air Forces and U.S. Air Force installations (my target audience is already familiar with the Air Force and its history).

Installations may be studied much like organizations or individuals—by noting the chronological events that occur during their service. So here is a look at terminology, designations and abbreviations, research documents, research sources, and miscellaneous tools.

While written from an Air Force perspective, much of this information will apply to the research of Army, Navy, or Marine Corps installations (especially airfields).


Here is a selection of common terms used when studying installations. I’ve categorized them as Description, Event, and Identification terms for ease in studying them—this is not an official categorization.

These are working definitions, gathered from a variety of sources and tempered with several years' experience reconciling the official definitions with the usage actually found in orders and publications.

Description Terms




A piece of real property owned or controlled by the military.


A generic term for an installation, usually used when referring to a primary installation.


A designation often applied to an off-base installation.


A designation often applied to a detached installation.


This refers to a standalone, or main, base.  


A subordinate installation, usually off-base to a primary installation.  It usually refers to an airfield, such as "Auxiliary Field" or "Air Force Auxiliary Field."


An installation that is subordinate to, and carried on the real property books of, a primary installation.  It also implies support of the primary installation's mission.


An installation which is supported by a primary installation, but which may have a mission totally unrelated to the supporting base.   The property may be owned by a different MAJCOM than the supporting base.

Detached Leased

Same as Detached but the property is leased rather than owned.


Refers to manufacturing or maintenance facilities, often designated as "Air Force Plant."


Indicates ownership, as in fee title to the land.


Real property interest in land that allows certain government use but stops short of ownership.  Easements are used for access roads, running wires or pipes, restricting construction, or other purposes when fee title to the land is not needed.

Continental United States (CONUS)

To the Air Force, this means the 48 contiguous states -- the "Lower 48."  (In the civilian world, the term continental United States includes Alaska.  The Air Force definition was in use long before Alaska gained statehood, and has not changed to keep up with the times.)

Event Terms




Officially creating (on paper) an installation.


The official designating of an installation as an "Air Force Base," "Auxiliary Field," etc.  Sometimes used interchangeably with "Name."


The official naming of an installation as "Randolph" "Falcon" etc.  Sometimes used interchangeably with "Designate."


To change the name of an installation, as to rename "Falcon AFB" as "Schriever AFB."  Sometimes used interchangeably with "Redesignate."

Date of Beneficial Occupancy (DOBO)

This is when an installation starts to be productively used, often before construction is complete.  This term is also used for new or renovated buildings.


To change the designation of an installation, as to redesignate "Cheyenne Mountain Air Force Base" to "Cheyenne Mountain Air Station."  Sometimes used interchangeably with "Rename."


Officially placing an installation into use.


Officially taking an installation out of use.


No longer needed to meet mission requirements.   An installation may be reported excess several times; such as excess to a main base, excess to a MAJCOM, excess to USAF, excess to DoD, etc.

Declaration of Taking

Filing of court papers by the government stating their intention of gaining fee title to property by condemnation proceedings.


Court process used by the government to legally take ownership of property under the concept of imminent domain (what Uncle Sam wants, Uncle Sam can take).  Typically used as a last resort when the property owner refuses to sell, and no other land will meet the need.

Identification Terms



Permanent Installation Number (PIN)

A unique identifying number assigned to an installation, a numeral between 0000 and 9999.  These are useful to the researcher because when an installation is renamed or redesignated the PIN normally stays the same.  The PIN outgrew its usefulness, since only 10,000 unique PINs could exist.   The earliest use of PINs I have found is the 1 Jul 56 USAF Installations Directory.  They were first listed on DAF orders on 30 Apr 57, and are last seen on a DAF order of 22 Jul 68.  TAC used PINs on orders as late as 30 Aug 68, and SAC used them on an order of 25 Sep 68. 

Installation Location Code (ILC) 

The successor to the PIN, expressed in alpha characters between AAAA and ZZZZ.  Different DoD users may refer to this as a Geographic Location Code, Location Code, or Installation Code.  The first use of ILCs I have found is on a CONAC order of 29 Apr 1964.  ILCs were first used on DAF orders on 10 Sep 68, and are still used.  In rare cases, a numeral may be included along with letters. 

Installation Location Kind (ILK)

Shows the installation kind in a three-letter code, such as ABS for Air Base.  These are fairly standardized codes used in DoD computer systems.  In many cases the ILK is different from the abbreviation used in correspondence, though occasionally an ILK will be found on an order in place of the normal text.


Designations and Abbreviations

Here is a list, by no means complete, of designations used by the Air Force, and their abbreviations.



Army Air Field


Army Air Base


Air Base


Air Force Station


Air Force Base


Air Station




Radar Bomb Scoring Site




Air Force Auxiliary Field


Air Force Range


Gap Filler Annex



Research Documents

General and Special Orders

Key events in an installation’s history are announced by the publication of a special order or general order. The Department of the Air Force (DAF) or the respective Major Command (MAJCOM) may publish the order (sometimes both). These orders are important to an installation's history much like promotion or PCS orders are important to a military person's career—they are the "official" source of the action they describe.  Orders are not always perfect!  They are occasionally published with errors and may be revoked, rescinded, or amended by later orders.

Directories and Station Lists

The USAF Installations Directory is a point-in-time listing providing information on the service’s inventory of installations. Prior to 1948, Army Air Forces Installations Directories, Army Air Forces Station Lists, and Air Corps Station Lists filled this same function. These documents give the installation name, location, command assignment, status, and possibly other information. They may show relationships between primary bases and off-base or detached installations. They may give details such as latitude and longitude coordinates, acreage, or runway specifics. Depending on the time period represented, these may or may not provide coverage of smaller detached or off-base installations.

A similar set of documents is the Army & Navy Directory of Airfields, or it’s modern equivalent, the Flight Information Publications. These are meant for use by flyers, so they will concentrate on the operational details of the installations.  And of course, only flying installations will be found here.

Major Commands (MAJCOMs) and Numbered Air Forces (NAFs) have also produced various directories and lists over the years. Depth and breadth of coverage varies considerably.

Layout Plans and Vicinity Maps

These are to an installation like a floor plan is to a house.  They show boundaries, building layouts, runway lengths, and other physical features.  Sometimes you can find helpful chronological information by studying the legend and tables on the plans.

MAJCOM or Unit Histories

These focus more on the operations of the unit or command than on the real property from which the units lived and worked. You may need to sift through hundreds of pages to find any good installation data, but it may be well worth the effort. The official history may offer insight not available from an order or a directory (selection process for the location, problems encountered in its acquisition and development, activities at the installation, maps, etc.).


Research Sources

Air Force Historical Research Agency (AFHRA)

This is the official repository of Air Force history.  They have quite a few Airfield Directories, Installation Directories, and related documents.  They also have tons (literally) of unit and command histories.

Air University Library (AUL)

This is one of the largest libraries, anywhere.  One of my favorite items is in the Authority Section.  They have a several-volume, bound-book set of DAF General and Special Orders from 1947 to the late 1970s.

United States Air Force Museum Research Division

More than just artifacts!  They have a wealth of research materials, including several Airfield Directories and similar documents.

MAJCOM and Wing History Offices

Some have more than others—due to focus on units versus bases.  You won't know what's there until you ask.  Be aware these offices are staffed to produce unit histories every six months; helping outside researchers is a secondary task.  They may allow you access to certain research materials but they won't (and shouldn't) do your research for you!

Air Force Base Libraries

You can find the occasional gem here.  In 1994, the Randolph AFB base library still had hard copies of Air Force magazine dating to the early 1950s.  The annual almanac issues have base listings that are quite handy -- plenty of Air Staff and MAJCOM action officers use these as a quick reference to AF bases around the world.

National Archives and Records Administration (NARA)

The official government document repositories.  The main repositories are in Washington DC and College Park, Maryland.  They also have regional facilities; for example the Fort Worth facility (Southwest Region) covers Texas, Oklahoma, Louisiana, and Arkansas.  The Southwest Region maintains a database of place names, which makes it easy to look up a former military base by name or nearest city (I'm not sure if other regions offer this service).  NARA maintains archives categorized in Record Groups, and here are some I have found useful:



Engineers, Office of the Chief of

RG 77

Farm Credit Administration

RG 103

Public Buildings Service

RG 121

General Services Administration

RG 269

War Assets Administration

RG 270

Federal Property Resources Service

RG 291

Air Force (Air Staff), Headquarters U.S.

RG 341

The GSA disposal case files in RG 269 are especially useful.  They typically include layout plans, real estate maps, brief histories of the property, and sometimes nice "for sale" flyers that describe exactly what the property consists of (including details like buildings, fuel tanks, generators, etc.).

Radomes, Inc. Online Radar Museum

Gene McManus and Tom Page lead Radomes, Inc. and the Online Radar Museum.  Their primary mission and current focus is to document Air Control and Warning (later called simply Radar) Squadrons which were in the United States, both the "lower 48" and Alaska.  They are also documenting certain overseas sites that were front-line Early Warning sites, located in Greenland and Iceland.  This is THE place to look for information on radar sites.

Ed Thelen's Nike Missile Web Site

This should be your first stop if you are looking for information on a Nike site.  Building on the published work of pioneer researcher Mark Morgan, Ed has gathered information on location and current status of Nike sites from a wide network of contributors (including yours truly as one of the "TerraServants".)


Miscellaneous Tools

Much of my research involves finding the locations of installations.  A basic understanding of latitude and longitude is very helpful; if you can find these coordinates in a document, you can then point to the location on a map, find it in mapping software, or find your way to the place with a Global Positioning System (GPS) receiver. I purchased my first GSP unit in 1995, but a modern smart phone has much more capability than that unit!  I do still use a 1998 vintage unit alongside my modern touch-screen unit because it displays latitude and longitude in large enough print to be useful when bouncing down back roads.   

Coordinates and Surveys

Many geographic coordinate systems exist, the most common being latitude (north/south) and longitude (east/west).  One obstacle here is the method of displaying the information; degrees-minutes-seconds (DD-MM-SS), or degrees-decimal minutes (DD-MM.MM).  Once in a while you'll encounter decimal degrees (DD.DDDD), just to keep it interesting!  I have built a quick-reference conversion chart (#1) for converting DD-MM-SS to DD-MM.MM and vice versa.  Also, based on increased popularity of the decimal degrees format among some users, I built a conversion chart (#2) for converting DD-MM-SS to DD.DDDD and vice versa.  At locations near the equator, a degree is about 60 miles, a minute is about one mile, and a second is about 88 feet.  This makes a handy rule of thumb when you're working with coordinates and maps.  There are several web sites that will do the conversion for you.

A college text on surveying may be helpful if you're just learning to use coordinate systems.  A common mistake of beginners is to think that 33-20-10 means the same thing as 33-20.10.  There's a big difference between that hyphen and that decimal point -- 10 seconds and .10 of a minute are two different things.  If you're puzzled by this, please find a textbook and study up before you try to work with latitude and longitude. 

Public land survey information describes locations in townships, ranges, and sections.  You can plug that information into the Land Survey Information System (look for the web site) to find the location on aerial imagery with latitude/longitude information.

Survey descriptions and metes and bounds descriptions are also useful in determining locations from layout plans, deeds, leases, and other real property documents.  A surveying textbook will give an explanation of surveying terms and how to use them.  Web sites such as can help make sense out of deeds platted in metes and bounds.

Maps and Charts

Among the best for installation research are the United States Geological Survey (USGS) topographical maps in scale 1:24,000.  This gives you a map covering about 7.5 x 7.5 miles, detailed enough to show individual buildings.  Many military installations will be clearly marked; sometimes by name or sometimes just by the title "MILITARY RESERVATION."  The 1:24,000 and 1:100,000 maps also show survey descriptions (township/range/section information) if applicable in that locality.  Even smaller scale, 1:250,000 scale maps also list some military installations and other features of interest (radar towers, etc.).  When I started this hobby in 1993, using these maps meant going to a library or a map store.  Now, you can just surf up The USGS Store and download all the current and historical topo maps you want, for free. 

The various types of aeronautical charts are useful for pinpointing an airfield if you know approximately where it is (or was). You may also locate bombing ranges by the Restricted Areas marking the airspace over the range.  Some navigation aids (radio range, radio beacon, VOR, etc.) will show on the charts, allowing you to locate some small off-base installations. Certain data about the airfield (runways, tower, radio, etc.) may be deciphered from the symbols on the chart, and from notes on the margins or reverse.  Back in the day you had to visit a pilot's supply store or order these charts by mail.  Now, you can surf up a web site called VFR MAP, and find all the current charts.

Aerial Imagery

The trailblazer for online hobbyist imagery was TerraServer, later called MSN Maps.  As of 2014 the web site has not been supported for a couple years, and operates only intermittently.  Fortunately we have other options now.  The latest "must have" is Google Earth.  You can view maps and imagery online at the Google web site, but download Google Earth to get the most of what they offer.  Google Earth is imagery only -- no maps -- but it gives you latitude/longitude coordinates, and they offer limited sets of historic imagery.  Another favorite of mine is Bing Maps, with their wonderful Bird's Eye aerial photos.  This low and close imagery is so good I sometimes determine from my desk whether a trip to a remote location is worthwhile or not.  Also useful is the Historic Aerials web site, because they have some older imagery that Google does not, plus you can switch between imagery and USGS topo maps.  Take your time and look at them all.