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Dedicated in 2007, this marker shares the history of a Texas plant that provided ammunition for the army from World War II through the Cold War era. Beginning as Longhorn Ordnance Works in 1941, the Longhorn Army Ammunition Plant was in service for over half a century. During these years, the plant saw multiple operational changes that reflected military history, such as switching between the production of munitions for artillery pieced to the production of rockets to better suit the needs of the Army. After the nuclear treaty between the U.S. and Soviet Union, the plant was slowly decommissioned and the land was restored as part of its transition to a wildlife refuge for the Caddo Lake region of East Texas.


  • Caddo Lake National Wildlife Refuge includes many remnants of the former munitions production complex.
  • The area around the Longhorn Army Ammunition Plant is heavily wooded and sits on the southwestern shore of Caddo Lake.
  • This map of the plant shows the scale of the facility prior to its conversion to a wildlife refuge.

As 1941 came to a close, the U.S. was preparing for entry into World War II and the Army Ordnance Department was looking for sites that would be suitable for a munitions plant. St. Louis’s Monsanto Chemical Company worked with the Army and selected this 8,500-acre site on the shores of Caddo Lake. Then a young congressman, Lyndon Baines Johnson used some of what would become his trademark art of political persuasion to broker the deal which provided employment near his wife's hometown of Karnack.  

The $22.5 million plant began operations on October 18, 1942. Within three years, the plant had produced over 400 million pounds of TNT for use in American munitions during WWII.  Following the end of the war, the plant was put on stand-by status, halting production operations for several years. When the Korean War began in the early 1950s, the demand for munitions rose quickly and the plant was brought back into operation under the management of the Universal Match Corporation of St. Louis.  

The 1950s saw the expansion of the plant’s mission to include the production of pyrotechnic devices and rocket propellant. In 1956, after gaining an Army contract to rehabilitate the plant, the Thiokol Corporation built a facility to produce solid propellant for the original Nike-Hercules rocket motors. Propellants and motors for missiles such as the Falcon and Sergeant missiles were also produced at the plant. This increase in production also saw an increase in capacity, with multiple new expansions being completed through the 1950s and 60s. 

1964 was the peak of the plant’s production and employment with nearly 3,000 personnel across 451 buildings. At that time, the complex was renamed the Longhorn Army Ammunition Plant. After the onset of the Vietnam War, the plat's focus shifted from rocket propellant to pyrotechnic ammunition and devices such as ground flares and signals. As the Vietnam War ended, employment dropped significantly and there were less than a thousand workers employed by the plant in 1975.  

In 1977, the plant was designated as a CORE facility for production of solid propellant rocket motors and pyrotechnic ammunition. This brought a modernization of the plant through the early 1980s, as well as the production of the first as second stages of the Pershing IA missile on the site. 

The beginning of the end for the Longhorn Army Ammunition Plant was the signing of the Treaty of Intermediate Nuclear Forces between the United States and the Soviet Union. This treaty required the destruction of an entire class of missiles and allowed Longhorn to play a significant historic role as the site where the first U.S. missiles were destroyed. Vice President George Bush said as he witnessed the destruction, “This is the day we began to reverse the arms race.” Soviet inspector Nikolai Shabalin remarked that the event proved “the world is by no means doomed to the nuclear arms race.” This demolition of arms at the plant continued until 1991.

1995 saw the official deactivation of Longhorn Army Ammunition Plant. In the years that followed, the site was repurposed to establish a national wildlife refuge by the U.S. Fish and Wildlife Service. Parts of the Longhorn land were declared Environmental Protection Agency Superfund sites, prompting extensive cleanup efforts to remove hazards, such as chemical wastes, while the USFWS focused on managing the area for conservation and protection of the indigenous birds and their habitat.  The LHAAP is now home to the Caddo Lake National Wildlife Refuge.

"Longhorn Army Ammunition Plant." Home - Atlas: Texas Historical Commission. Accessed March 09, 2019. https://atlas.thc.state.tx.us/Details/5507015018.

Odintz, Mark. "LONGHORN ARMY AMMUNITION PLANT." The Handbook of Texas Online| Texas State Historical Association (TSHA). June 15, 2010. Accessed March 09, 2019. https://tshaonline.org/handbook/online/articles/dml03.

"History of the Longhorn Army Ammunition Plant." Caddo Lake. U.S. Fish and Wildlife Service. August 17, 2012. Accessed March 09, 2019. https://www.fws.gov/refuge/Caddo_Lake/about/amm_plant.html.