The collection is comprised of letters, financial documents, and biographical and estate records of Justus Post spanning from 1807 to circa 1999. The bulk of the collection consists of letters, and several transcriptions, written by Justus Post to his older brother, John Post, from 1807 to 1821. The collection is arranged alphabetically by folder title.

Justus wrote the earliest letters, 1807-1814, while in the army and stationed at various places such West Point, Philadelphia, and Fort Columbus (New York Harbor). He writes of family, the places he has traveled, and of current affairs, particularly events leading up to and including the War of 1812. Justus wrote one last letter to John before his family left New York for the Missouri Territory on 14 August 1815.

Letters subsequent to Justus’s arrival in St. Louis often focus upon his land deals in Missouri and Illinois, his travels, news of friend and colleagues relocating in the west, and asking John to join him in Missouri. On 14 June 1819, Justus wrote about a blacksmith, Mr. Robley, and a wagon maker, Mr. Griswold, opening for business in his town of Chesterfield and of his plans for further development of the town.

The final letter in the collection, 1 March 1832, is the only one not written by Justus. Henry and Maria Griswold, one of John Post’s daughters, wrote to “Respected Parents, Brothers & Sisters,” and addressed the letter to John Post of Bonhomme, Missouri. The letter relates family news and their journey home from St. Louis.

Additions to the collection include a volume, a portion of which contains a register of banking transactions from July 1819 to December 1821 (acc. no.2009.145). The bank register does not include name of bank but lists several transactions for the Missouri Exchange Bank. Entries include information such as holders of notes/bills, designation (bill or note), drawers and endorsers, acceptors or payers, amount, and remarks (“paid” or “returned” with date). The other part of the volume relates to the estate of Justus Post. It includes an inventory/appraisal (12 May 1846), an inventory of property to Eliza Post, and bills of sale (4-8 June 1846).

Financial documents in the collection include Justus Post’s final account as Quartermaster General dated 31 March 1815. There is also a list of his Missouri real estate holdings that he shared with his brother John in 1819. The Post family bought slaves for the first time after their arrival in Missouri. There are photocopies of two slave bills of sale, 9 January 1816 and 17 November 1817. On 19 August 1830, Justus sold land in Bonhomme to John M. Ficklin. In 1839, Justus Post purchased stock in the Caledonia Railroad and Manufacturing Company.