This collection consists of the papers of Jonathan Rhea, and papers of others, most likely related to his legal office. More than half of the collection is not directly associated with Rhea, and much of this material was created after Rhea's death in 1815.

Series 1, "Papers of Jonathan Rhea," dates from 1786 to 1814 and is almost entirely legal in nature. Researchers will find accounts, bills, promissory notes, receipts, land transactions, court records, and correspondence, which makes up the bulk of this series. The correspondence is arranged alphabetically by author, and all but five letters are addressed to Rhea. The five letters not addressed to Rhea were written by Rhea to Robert Montgomery and Colonel Joshua Howell. The two letters written to Colonel Joshua Howell describe the "Insurrection at Princeton," also known as the "Great Rebellion" at Princeton in 1807, when several College of New Jersey students resisted the authority of the College and, in particular, President Samuel Stanhope Smith. Of interest, and of a more personal nature, are the bills from Pearsons for the building of Rhea's home in 1810.

Series 2, "Papers of Others," dates from 1774 to 1892, and like the first series, is almost entirely legal in nature. The bulk of this series is correspondence, which is arranged alphabetically by author. Some of the recipients include John Baggs, Rachel (or Rachael) Borden, Jesse Bowen, James Imlay, John Johnston, Benjamin F. Lee, William B. Manning, Samuel Reid, Nathaniel Smith, and John Wachsmith. The correspondence mainly refers to legal matters, and may relate to the court records, which are arranged by court. Researchers will also find financial records, land records, military records, and wills.

It is unclear how all the authors, recipients, and papers are related to Jonathan Rhea. Some materials were created by, received by, or reference Rhea's relatives, including his uncle and Sheriff of Monmouth County, Colonel David Rhea (1740-1821); his wife's uncle and Sheriff of Monmouth County, David Forman (1733-1812); his son, Nicholas Rhea (1792-1817), a graduate of the College of New Jersey (now Princeton University); his son-in-law and colleague, Garret Dorset Wall (1783-1850); and his nephew, William W. Montgomery (1778-1864). Others, including Charles Ewing and James H. Imlay, were colleagues.