Boundary Field is a former Florida Avenue, NW. It was just outside what was then the city limit of Washington, whose northern boundary was Boundary Street (later renamed Florida Avenue).
The ground was home to the Washington Senators of the American Association in 1891 and then of the National League from 1892 to 1899 after the League absorbed the Association. The League contracted after the 1899 season and the Senators folded.
From 1891 to 1893, the field was the venue for home games of the Georgetown Hoyas football program.
The field was also called National Park as the home of the American League's Washington Nationals from 1903 to 1911. When the American League declared itself a major league and began raiding National League rosters for talent, the National League decided to retain its lease on the Boundary Field property. This forced the Nationals to find a new home, and they settled upon a field with the prosaic name American League Park.
After peace was made between the two leagues, the Nationals moved to the old Boundary Field location. They played there for the next eight seasons. In 1909, the annual Congressional Baseball Game was begun, and was held at this venue and its successor for the next few decades