The Department of Energy had owned and managed most of the properties located within the three different sites. For over ten years, the DoE worked with the National Park Service and federal, state and local governments and agencies with the intention of turning places of importance into a National Historical Park. After several years of surveying the three sites and five other possible alternatives, the two agencies officially recommended a historical park be established in Hanford, Los Alamos and Oak Ridge. The Department of Energy would continue to manage and own the sites while the National Park Service would provide interpretive services, visitor centers and park rangers. After two unsuccessful attempts at passing a bill in Congress authorizing the park in 2012 and 2013, the House and Senate ultimately passed the bill in December 2014, with President Obama signing the National Defense Authorization Act shortly thereafter which authorized the Manhattan Project National Historical Park.

Hanford, Washington

• B Reactor National Historic Landmark – bus tours are available by advance reservation
• the previous Hanford High School in the former Town of Hanford and Hanford Construction Camp Historic District
• Bruggemann's Agricultural Warehouse Complex
• White Bluffs Bank and Hanford Irrigation District Pump House

Los Alamos, New Mexico

The Los Alamos visitor center for the Manhattan Project NHP is located at 475 20th Street in downtown Los Alamos. This location is open daily 9-4 weather and staffing permitting. It is in the Los Alamos Community Building on the front left as you face the building from the street (next to the teen center). At the visitor center, visitors can learn about the Manhattan Project and related sites in the vicinity.

There are 3 locations of park that are on Los Alamos National Laboratory property. These locations are currently not open to the public:

• Gun Site Facilities: three bunkered buildings (TA-8-1, TA-8-2, and TA-8-3), and a portable guard shack (TA-8-172).
• V-Site Facilities: TA-16-516 and TA-16-517 V-Site Assembly Building
• Pajarito Site: TA-18-1 Slotin Building, TA-8-2 Battleship Control Building, and the TA-18-29 Pond Cabin.

Controls of the X-10 Graphite Reactor

Oak Ridge, Tennessee

The American Museum of Science and Energy provides bus tours of several buildings in the Clinton Engineer Works including the:

• X-10 Graphite Reactor
• Buildings 9731 and 9204-3 at the Y-12 complex
• East Tennessee Technology Park, located on the site of the K-25 Building