Gaithersburg Latitude Observatory
Historic district in Maryland. Added to the National Register in 1985, and a National Historic Landmark.
What it is
The Gaithersburg Latitude Observatory is a historic astronomical observatory on DeSellum Avenue in Gaithersburg, Maryland. It was established in 1899 as part of a system of six International Latitude Observatories to precisely measure the wobble of the Earth's rotating axis. The observatory building and adjacent monuments were designated a National Historic Landmark in 1989 as a testament to international scientific cooperation. The observatory was taken out of service in 1982 after automation eliminated the need for human observations; the property is now owned by the city.
Text from Wikipedia, CC BY-SA 4.0.
The record
| Property type | Historic district |
| Address | 100 DeSellum Ave, Gaithersburg, MD |
| County | Montgomery County |
| Listed | Jul 12, 1985 |
| Listed for | Science |
| Level of significance | National |
| Reference number | 85001578 |
| Type of place | observatory |
| Designations | National Historic Landmark |
| Contributing resources | 1 building, 1 structure, 5 objects |
The nomination form, the document that argues why this place matters, is in the National Archives: Read the nomination ↗
Visiting
| Address | 100 DeSellum Ave, Gaithersburg, MD |
| Coordinates | 39.1367° N, 77.1988° W · Directions ↗ |
| Nearest national park unit | Chesapeake & Ohio Canal National Historical Park · 10 miles · on Park Atlas |
| Federal campgrounds nearby | Swains Lock Hiker-Biker Campsite 8 miles · Marsden Tract Group Campsite 11 miles · Carderock Recreation Area Pavilion 11 miles |
Explore
Drawings & photographs
Measured drawings and photographs from the Library of Congress. Public domain. All 7 records ↗
Map
Nearby in Montgomery County
Local history books for Montgomery County
We earn a small commission if you buy through these links. It does not change what we list.
- Culinary History of Montgomery County, MarylandClaudia Kousoulas and Ellen Letourneau, 2022Find at Bookshop.org
Guidebooks to historic places in Maryland
Titles come from Open Library's catalog, matched by subject heading or by title.
Reference
Questions people ask
When was Gaithersburg Latitude Observatory listed on the National Register?
Jul 12, 1985. It is also a National Historic Landmark, the higher of the two designations.
Source: National Park Service
Where is Gaithersburg Latitude Observatory?
100 DeSellum Ave, Gaithersburg, Montgomery County, Maryland. The nearest national park unit is Chesapeake & Ohio Canal National Historical Park, 10 miles away.
What does the Gaithersburg Latitude Observatory listing include?
The listing counts 7 contributing resources. Those are 1 building, 1 structure, and 5 objects. A contributing resource is a part of the listed property that carries its historic significance.
Source: National Park Service
Are there historic photographs or drawings of Gaithersburg Latitude Observatory?
Yes. The Historic American Buildings Survey at the Library of Congress has drawings or photographs of it.
Source: Library of Congress
Where is the nomination form for Gaithersburg Latitude Observatory?
The National Archives holds the nomination form, the document that made the case for listing.
Source: National Archives
Are there campgrounds near Gaithersburg Latitude Observatory?
Three federal campgrounds are within reach. The closest is Swains Lock Hiker-Biker Campsite, 8 miles away. Marsden Tract Group Campsite is 11 miles away, and Carderock Recreation Area Pavilion is 11 miles away.
Source: Campsite Atlas
Is there cell service at Gaithersburg Latitude Observatory?
FCC coverage maps show Verizon 5G, AT&T 5G, and T-Mobile 5G at the listed point. Coverage indoors and behind old masonry is another matter.
Source: FCC Broadband Map
Sources
Location, type and contributing counts come from the National Park Service's National Register spatial data. Listing dates come from the National Register office's spreadsheet where it carries the listing. Construction date, architect, style, photograph and encyclopedia link come from Wikidata and Wikimedia Commons, matched on reference number 85001578. Nothing here is transcribed by hand. The nomination form and photographs ↗ at NPGallery are the original nomination as filed with the National Park Service, and the form is often the best description of the place. The description under "What it is" is the opening of the Wikipedia article, CC BY-SA. Drawings and photographs are Historic American Buildings Survey records at the Library of Congress, public domain.