Located just north of the city of Richland, in the southeastern part of Washington State, the 586-square-mile Hanford Site is managed by the U.S. Department of Energy's (DOE) Richland Operations Office.

Hanford was established in secrecy during World War II to produce plutonium for an atomic bomb. Peak nuclear materials production was reached in the 1960s, when eight reactors were in operation. Altogether, Hanford supplied plutonium for the United States nuclear weapons defense for more than four decades. All weapons material production was halted in the late 1980s, and Hanford is now engaged in the world's largest environmental cleanup project.

With a workforce of approximately 11,000 and an annual budget of nearly $1.4 billion dollars, Hanford is vigorously pursuing three cleanup outcomes: restoring the Columbia River Corridor, transitioning the central part of the Hanford Site for waste treatment and long-term storage, and putting DOE's assets, including the Pacific Northwest National Laboratory, to work solving regional and global environmental problems.

DOE leases some of Hanford's land to the State of Washington, which in turn leases it out for two independent operations. U.S. Ecology operates a low-level waste burial ground for commercial waste, and Energy Northwest, a consortium of public utility companies, oversees the northwest's only operating commercial power reactor.

In May, 1989, DOE, the U.S. Environmental Protection Agency, and the Washington State Department of Ecology signed the landmark Hanford Federal Facility Agreement and Consent Order, commonly known as the Tri-Party Agreement (TPA). The TPA outlines legally enforceable milestones for Hanford cleanup over the next several decades.