Boundary Field, also known as American League Park II and National Park, is a former baseball ground located in Washington, D.C. located on a larger block bounded approximately by Georgia Avenue, 5th Street, W Street and 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 National League contracted after the 1899 season and the Senators folded. From 1891 to 1893, the field was also the venue for home games of the Georgetown Hoyas football program.
The field was also the home of the American League's Washington Senators/Nationals from 1904 through 1910. When the American League declared itself a major league in 1901 and began raiding National League rosters for talent, the NL decided to retain its lease on the Boundary Field property. This forced the American League's new reincarnation of the Senators to find an alternative home field, and they settled upon a field in Northeast DC with the prosaic name American League Park.
After peace was made between the two leagues in 1903, the Senators moved to the old Boundary Field location, which was subsequently also referred to as American League Park. (Today, the terms "American League Park I" and "American League Park II" are used to make the distinction.) When the Senators were rebranded as the Nationals, the park was also referred to as National Park. The Senators/Nationals played there through the 1910 season. In 1909, the annual Congressional Baseball Game was begun, and was held at this venue and its successor for the next several decades.
The wooden stands were destroyed by fire on March 17, 1911. The structure was rebuilt in steel and concrete as the ballpark that would later be known as Griffith Stadium.