Researching Aerial Photography of the United States : RG 145 Aerial Indexes Now Digitized

The Cartographic Branch holds aerial imagery covering much of the United States and also many areas around the world. Today’s post will focus on getting started with aerial imagery covering the United States, and specifically, Record Group (RG) 145 imagery. For more information on locating foreign aerial photography, see our previous posts: Researching Foreign Aerial Photography and Researching Foreign Aerial Photography – Captured German Aerial Prints.

The bulk of Cartographic Branch’s aerial photography holdings dates from the 1930s to the 1950s, although some coverage is available outside of those dates. This aerial photography is held within four main record groups: RG 145, RG 114, RG 95, and RG 373. Coverage can also be found in some other record groups, which are included in the domestic aerial finding aid, Special List 25.

1950 - BVO - Van Wert
Example of an aerial photography from RG 145. This aerial photograph shows Van Wert County, Ohio and dates from 1950. RG 145, Can #ON039465, BVO-3G-15.

To get started researching aerials for an area in the United States, first check Special List 25. This finding aid, which is arranged by state and county, lists aerial coverage, including the coverage years, and the record group. It is available for download as a spreadsheet at the following link: Special List 25 – United States or is available to view and use in our research room.

To start, select the sheet tab at the bottom for the state. Next, look for the county. For our example, we will look at Van Wert County, Ohio.

Special List 25 example - Van Wert County, Ohio
Example showing Special List 25, the main finding aid to locate aerial coverage of the United States. This finding aid provides information concerning the record group and year for coverage of a specific county. Our example, Van Wert County, Ohio, is outlined in blue.

Column A lists the County/Area. Column B lists the project symbol associated with the photography project. Column C lists the year. A “p” following the year means that there is partial coverage for that county and year. Column D lists the Record Group (RG). For Van Wert County (outlined in blue), there is coverage within RG 373, RG 145, and RG 57. RG 373 domestic imagery is located the same way as RG 373 foreign imagery using the overlay indexes that are available through the National Archives Catalog. See our post on Researching Foreign Aerial Photography for more information. RG 57 indexes are available to request and view in our research room.

The next step in the process is to locate your area(s) of interest on the aerial index sheet. Each aerial index sheet is a photo mosaic comprised of many small squares that represent  individual photographic frames. The aerial indexes for RG 145 from the 1930s through approximately 1953 were recently digitized and are now available online through the National Archives Catalog.  We are in the process of digitizing and making the index sheets from other record groups, including RG 114 and RG 95, available in the catalog as well. Indexes not available through our online catalog can be requested and viewed in person in our research room.

To locate the aerial indexes in our catalog for a particular county, we recommend using the advanced search option, and entering the county and state name, along with the term “aerial index” (example: Van Wert County Ohio Aerial Index) in the search term field, and then selecting File Unit for the Level of Descriptions field and National Archives at College Park – Cartographic Branch for the location of materials field. This search should yield results similar to the screenshot below:

Catalog Search for Indexes Example
Example of National Archives Catalog search results showing aerial indexes for Van County, Ohio from 1939 and 1950.

Click on the year of interest. Then, under the details section, click on the blue hyperlink next to “includes.” This will take you to the individual sheet or sheets of aerial indexes. If no blue hyperlink appears next to includes, this means that these aerial index sheets are not yet available electronically in our catalog.

1939 Van Wert Index Example
Example of a catalog entry for aerial index sheets, in this case for Van Wert County, Ohio, from 1939. The black circle shows the hyperlink to click to view the individual sheets. If no hyperlink appears in this location, this means that the indexes are not yet available through our online catalog and need to be requested and viewed in person in our research room.

Each photographic exposure taken during the aerial photography project is shown as a square on the aerial indexes. Note that there is significant overlap between frames, so your area may be covered on more than one frame. Locate your area of interest on the aerial index sheets. You may need to compare the aerial index sheet to a topographical map in order to find your location. Remember that roads, highways, interstates, building, and other landmarks may have changed over time, especially from the 1930s to today.

1939 BVO county index with darker square
1939 photomosaic index sheet for Van Wert County, Ohio. The black square indicates our example area of interest, which is identified in the upper right corner as BVO-7-18.

In the upper corner of each square on the photomosaic index is the symbol, roll, and frame number. For our example, this information is BVO-7-18. BVO is the project symbol, 7 is the roll number, and 18 is the frame number. The symbol and roll number are required to locate the actual rolled aerial negatives.

BVO-7-18 symbol example
Example showing the location of the symbol, roll and frame number in the upper right corner of the frame. For this example, the symbol is BVO, the roll is 7, and the frame number is 18.

After locating the roll and spot number, the next step is to check our Can Locators, which are available both electronically and as a hard copy in our research room or may be downloaded as a spreadsheet at the following link: RG 145 Can Locator. Look up the symbol and roll number to determine which can of rolled aerial negatives contains the specific imagery. If the can is a “DN” can, that means that it is a duplicate and is available to request in our College Park research room as a normal pull. If the number is an “ON” number, that means it is an original negative and is stored off-site in cold storage for preservation reasons. ON cans need to be ordered and then can be viewed in our College Park research room. There is approximately a 3 business day delay before the film is available for use.

Can locator example with arrow 2
Example of RG 145 Can Locator, which matched the symbol and roll found using the aerial index to the can number containing that specific rolled aerial film. The black arrow shows the information for our example, BVO-7. In this case, in the NARA Can Column, we learn that this photography can be found on Can # DN0805. This can is available to request and view as a same day pull in our research room. However, note the can one line above, which is ON215982. ON cans such as this one are stored in cold storage for preservation reasons and must be ordered using the can number and barcode found in the locator. There is an approximately 3 business day delay before these cans be made available to view in our College Park research room.

In our research room, we have light tables and aerial scanners that are available to view and copy aerial photography. More information about these options can be found on our post about Foreign Aerial Photography.

1939 - BVO - Van Wert
This scanned aerial image is the final result of our search for aerial imagery covering an area of Van Wert County, Ohio. (BVO-7-18, Can # DN0805.)

Cartographic reference staff are available daily to assist with aerial questions in person in our research room at the National Archives at College Park, Maryland.

2 thoughts on “Researching Aerial Photography of the United States : RG 145 Aerial Indexes Now Digitized

Comments are closed.