Great Falls Nike Fire Control Site W-83 – Great Falls, Virginia - Atlas Obscura

Great Falls Nike Fire Control Site W-83

Great Falls, Virginia

This former Cold War missile control site played an important role in the creation of GPS.  

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This site is one of 13 different Nike Integrated Fire Control Sites that were erected around the greater Washington D.C. and Baltimore area. The Great Falls Nike Integrated Fire Control Site not only played a part in the United States’s defense against an aerial attack, but was also crucial in the development of the Global Positioning System (GPS).

In 1954, the U.S. government purchased 12 acres of land from local dairy farmer Mark Turner, with plans to construct a Nike Integrated Fire Control Site to coincide with the Nike Missile Launch Site that was already under construction along Utterback Store Road. 

Activated in 1955, the Great Falls Nike Integrated Fire Control Site was one of many Nike Integrated Fire Control Sites crafted during the Cold War and was designed to defend against an air attack. This facility was located about a mile downrange from its respective launch area.

The Integrated Fire Control Site consisted of various structures including barracks, a mess hall, offices, and two radar towers. These towers were equipped with High-Power Acquisition Radar (HIPAR) and Missile Tracking Radar. In 1962, both the Nike Integrated Fire Control Site and the Launch Site ceased operations.

After its initial closure in 1962, the property became a research station for the U.S. Army Map Service’s efforts in geo-location and navigation. It was here that the Map Service initiated a significant satellite tracking program that would eventually become part of the Defense Mapping Agency in 1972.

This tracking system greatly contributed to the Global Positioning System (GPS), and as stated on one of the site’s historical markers, the data collected would allow, “geospatial scientists to establish precise geographical reference points on the Earth’s surface and to refine their estimates of the Earth’s true shape and variations in its gravity field.” The facility closed again in 1993.

In 1999, the land was transferred to the Fairfax County Park Authority with the intention of turning the former site into a public park and observatory. Between 2000 and 2002, all of the facility’s former structures were torn down, with the exception of the two radar towers.

The southern radar tower was repurposed as an observatory when the facility was utilized by the Army Map Service, though in 2010, the massive dome was replaced with a newer and much stronger telescope. In 2016, a roll-top observatory building was constructed next to the southern radar tower, this building not only features a roll-top roof, but also a classroom area utilized by visiting schools.

Know Before You Go

Known today as Observatory Park, the site can be accessed off of Springvale Road (just south of the Georgetown Pike), with both radar towers clearly visible from the road.


The park also features a playground and gazebo area just west of its parking lot which are accessible to the public from dusk to dawn any day of the week. The roll-top observatory is open to the public on Friday evenings free-of-charge, with special viewings taking place during eclipses and meteor showers.