Arden Hills Army Training Site

The Arden Hills Army Training Site (AHATS) is a United States Army National Guard training installation in Arden Hills, Minnesota, operated by the Minnesota Army National Guard. The site covers approximately 1,500 acres (6.1 km²) in Ramsey County, Minnesota and serves as the headquarters of the 34th Infantry Division.^[1][2]

The installation occupies a portion of the former Twin Cities Army Ammunition Plant (TCAAP), a federal munitions facility established in 1941. Portions of the former plant site were listed on the National Priorities List in 1983, and remediation has been ongoing under federal and state oversight.^[3][4]

In 2020, the Minnesota Army National Guard opened the General John W. Vessey Readiness Center at AHATS.^[5] Adjacent former TCAAP land is being redeveloped as Rice Creek Commons, with construction beginning in 2025.^[6]

Built in 1941 as the Twin Cities Ordnance Plant (later TCAAP), the site was a government-owned, contractor-operated facility that produced small-arms ammunition during World War II, the Korean War, and the Vietnam War.^[7] At its wartime peak, the facility employed approximately 26,000 workers, including a large percentage of women and an integrated workforce.^[8]

After its final standby period, the Army declared the property excess in 1994 under the Base Realignment and Closure process. Approximately 1,500 acres (6.1 km²) were transferred to the Minnesota National Guard, which designated the parcel as the Arden Hills Army Training Site. The Army formally closed TCAAP in 2005.^[9][1]

In 1981, testing of municipal water supply wells in neighboring New Brighton detected trichloroethylene (TCE) traced to the TCAAP site.^[3] In 1983, the United States Environmental Protection Agency (EPA) placed TCAAP on the National Priorities List, making it the largest Superfund site in Minnesota.^[3] A 1987 Federal Facility Agreement between the EPA, the United States Army, and the Minnesota Pollution Control Agency (MPCA) established the cleanup framework. Investigations found chlorinated solvents and other contaminants in soil and groundwater on and off the former plant grounds.^[3]

By the 2010s, the EPA reported that tens of thousands of cubic yards of contaminated soil had been removed and treated.^[3] In 2015, the MPCA certified a 427 acres (1.73 km²) parcel as meeting cleanup standards for redevelopment.^[10] The EPA partially delisted portions of the site from the NPL in 2019,^[11] and in 2022 selected dredging as the remedy for Round Lake's contaminated sediments.^[4] The EPA identifies PFAS as an emerging contaminant at the site that is still being studied.^[3]

The Arden Hills Army Training Site is a training area for the Minnesota Army National Guard. According to the Minnesota National Guard, the site supports training for more than 1,500 soldiers annually.^[1] The facility is also used for training exercises by other military services and law enforcement agencies, including the Ramsey County Sheriff's Office.^[1][7]

The 34th Infantry Division ("Red Bulls") relocated its headquarters to AHATS in November 2020.^[2] The site also serves as the headquarters for the 834th Aviation Support Battalion, which supports Black Hawk and Chinook helicopter operations.^[1][12] In January 2026, the 1st Armored Brigade Combat Team, which had been temporarily stationed at AHATS, relocated to its permanent home station at the Rosemount Armory.^[13]

Training infrastructure at the site includes administrative offices, classrooms, a weapons vault, and vehicle maintenance bays.^[1] The installation's simulation centers are used for virtual tactical exercises.^[1]

The General John W. Vessey Readiness Center is a 149,735-square-foot (13,910.8 m²) military facility that opened in 2020. Designed by LEO A DALY at a cost of approximately $39 million, the center achieved LEED Gold certification.^[5]

The readiness center is named for General John W. Vessey Jr. (1922–2016), a Minneapolis native and former Chairman of the Joint Chiefs of Staff.^[5] The facility uses geothermal heating and cooling and rooftop solar power.^[5] In 2022, the project received the Grand Design Award from the Society of American Military Engineers (SAME).^[5]

The Ben Franklin Readiness Center is a 64,000-square-foot facility located on the AHATS property. It provides administrative, training, and secure storage space for various tenant units, including the 147th Human Resources Company.^[14][15] The facility was designed to meet LEED Silver standards and includes geothermal wells and rain gardens for stormwater management.^[14]

Large areas of the AHATS property remained undeveloped during its decades as a restricted federal site, and native habitats survived.^[16] Audubon Minnesota designated the installation as an Important Bird Area, and surveys have documented over 200 bird species at the site. Habitats include remnant tallgrass prairie, oak savanna, and wetlands.^[16][17]

The Rice Creek North Regional Trail traverses a portion of the AHATS property. The paved multi-use trail, opened in 2008, connects five municipalities in the northern Twin Cities metropolitan area and forms part of the Ramsey County regional trail network.^[18]

On adjacent former TCAAP land, Ramsey County is developing Rice Creek Commons, a mixed-use community on a 427 acres (1.73 km²) parcel purchased from the federal government in 2013.^[10][19] In April 2025, officials broke ground on the first construction project.^[6] The project is a long-term redevelopment expected to total approximately $1 billion in investment.^[19]

• Arden Hills Army Training Site — Minnesota National Guard