Jefferson Street Grounds

Jefferson Street Grounds was a baseball field located in Philadelphia, Pennsylvania. It was also known as Jefferson Park and Athletics Park. It was home to the Philadelphia Athletics from 1871 to 1876, five seasons in the National Association and one in the National League of Base Ball Clubs. From 1873 to 1875, the Athletics shared it with the White Stockings, also in the National Association. Later it was home to the American Association Athletics beginning 1883, moving in from Oakdale Park, until 1890.

The grounds were located on a large block bounded by Jefferson Street (north); 25th Street (east); Master Street (south); and 27th Street (west). Although typically listed as one ballpark, the 1870s diamond was located in the opposite corner of the block from the 1880s diamond. The facility opened on May 15, 1871. The seating capacity was meager, only 5,000 seats. The inaugural National League game was played there, on Saturday, April 22, 1876, between the Philadelphia Athletics and the Boston Red Caps; Boston won 6-5. By a quirk of fate, it was the only NL game played that day, all others being rained out. This game is often pointed to as the beginning of Major League Baseball.

The last major league game played in the park was October 11, 1890.

The ballpark site is currently occupied by various structures including Daniel Boone Public School aka Camelot Academy at 1435 N 26th St, and the Athletic Recreation Center and its ball fields.