Answer: A school for girls, the Mary Anna Longstreth School. 

Mary Anna Longstreth was born in Philadelphia in 1811 to Isaac T. Longstreth and Mary Collins. In 1829, she and her younger sister Susan decided to start up a school for girls. During the summer, a private residence at 3 North Eleventh Street was acquired and the Longstreth's school began there with five children in September 1829. (The house also served as quarters for members of the Longstreth family.) The class size quickly reached fourteen in early 1830. To help with classes, Mary Anna and Susan were later joined by their younger sister. Elizabeth. She stayed with the school until she married Israel Morris in 1839, by which time the school had grown to accommodate several dozen students. In 1836, the school was moved to Eleventh and Cherry streets where a large house and garden were built.

Susan Longstreth retired from the school in the 1840 dues to health issues, and Mary Anna kept the school going until her own retirement in 1877. In 1857, further growth in the number of students at the Longstreth school prompted another move, this time to a larger building at Filbert and Juniper streets. There is remained until the late 1860s, when the school moved once more to Merrick Street (Broad Street) on Penn Square (City Hall). The Longstreth school closed in June 1877, and Mary Anna Longstreth died in August 1884.

HSP holds a collection of records from the Mary Anna Longstreth Alumnae Association (#1159) that contains administrative and financial papers, as well as correspondence of the organization dating from the 1800s to the early 1900s. For more information on Longstreth, see Memoir of Mary Anna Longstreth by Margaret Newlin (call number Gl .86 or Gl .861).