Answer: Rawle and Henderson.

In 1983, on the 200^th anniversary of its founding, Rawle & Henderson in Philadelphia was recognized by the United States Senate under Resolution 451 as “the oldest law firm in continuous practice in the United States.”  The firm was founded by William Rawle as the Rawle Law Offices in 1783, the same year that he was admitted to the bar.  Later, Rawle was elected to the Pennsylvania Constitutional Assembly in 1787 and was appointed Pennsylvania’s first United States attorney by President George Washington in 1791. 

Rawle was also a civic leader.  He helped to establish the Historical Society of Pennsylvania in 1824 and served as the organization’s first president.  Rawle was a member of the American Philosophical Society and president of the local anti-slavery society.

Throughout the 1800s, subsequent generations of Rawle men continued to lead the law offices and served as founding or contributing members of several Philadelphia organizations, including the Historical Society of Pennsylvania, the American Philosophical Society, the University of Pennsylvania, the Library Company of Philadelphia, and the Pennsylvania Academy of Fine Arts. 

In 1913, the firm became known as Rawle and Henderson with the addition of Joseph W. Henderson; he became a full partner in 1917.  The firm continues to be one of the region’s leading practices, particularly in admiralty and maritime law.

The Rawle & Henderson collection (#3109) at HSP consists of sixty-three law books kept by the firm, the earliest dating to 1800.  HSP also holds a substantial collection of papers from the Rawle family (#536) that contains legal documents related to the firm of William Rawle and his descendants, personal and professional correspondence, and genealogical material.