There was one non-negotiable condition under which Major League Baseball would approve the relocation of the Montreal Expos to Washington D.C.: the city government had to agree to fully fund a new stadium with all the modern amenities and at least 40,000 seats. After a series of bizarre political maneuverings between the Mayor's office and the D.C. Council, final approval of a revised deal was reached at the last minute in March 2005, mere weeks before the new Nationals team was scheduled to begin playing. As soon as the sale of the Nationals franchise was consummated, construction began in May 2006.
Note that the outfield dimensions are subject to change as construction nears completion. The playing field will be about 15 feet below street level.
Various industrial buildings, run-down row houses, bars, a Volvo repair shop, an artist studio, and a recycling center used to be located on this site. Nearby are (or were) Metro bus yards, a cement plant, and the Good and Plenty carry-out / eatery. The Federal Center Southeast office building complex and the historic Navy Yards are situated on the east side.