Written by Jody Trammel

Gaithersburg Latitude Observatory

Gaithersburg Latitude ObservatoryIf you happen to visit Gaithersburg in Montgomery County, you will find out the Gaithersburg Latitude Observatory is one of its premier attractions. The beacon is located on a 2.3 acre property at the southern end of the city.

In case you want to see the observatory and get a ride back to the airport at the end of your visit, call Affinity Airport Sedan. Our professional car service will pick you up and get you were you need to be.


The Gaithersburg Observatory was put up under the stewardship of Edwin Smith, Chief of the Instrument Division of the United States Coast and Geodetic Survey between 1891 and 1892. However, it only became operational in October of 1899. This agency is now called the National Oceanic and Atmospheric Administration which operates the International Polar Motion Service Observatories.

Smith lived in Rockville, Maryland. When the International Geodetic Association provided funds for the acquisition of property in 1898, Smith took the lead in the building of the Gaithersburg Observatory. The City Council of Gaithersburg named the observatory as a local historic site in December, 1983. The site was listed in the National Register of Historic Places in 1985. And it was turned over by the federal government to the city of Gaithersburg in May of 1987. It was meant to be preserved as a historic memorial and used for public welfare. Noe the City Council plans to refurbish the facility and construct a science education center for the use by school children of Gaithersburg.


The Latitude Observatory is a small one-story edifice. The structure has a concrete mortar and fieldstone foundation. South of the observatory is the Meridian Mark Pier. It is a green metal pagoda-shaped satructure which is four feet high by two feet. It was used to bring into line the Zenith Telescope. Five Coast and Geodetic Survey monuments are located on the property. These monuments determine precise geographic longitude and latitude positions, elevation above sea level, and direction of the magnetic north field of force.

The scientific work conducted at the Gaithersburg Latitude Observatory demonstrated the systematic approach utilized by the International Geodetic Association to measure the degree of trembling that took place at the earth’s north-south axis. This observatory and five other centers in other countries were responsible for gathering information which is still being used by modern scientists. The Gaithersburg observatory operated until 1982 when computerization rendered manual observation obsolete.