John Claudius L'Engle (1800-1864) was a lawyer, slaveholder, and well- known resident of Jacksonville, Florida. In 1830 L'Engle married Susan Philippa Fatio (1806-1895) from the prominent Fatio family. They had eleven children including Edward McCrady, a Confederate Captain, and Francis Philip, father of Claude L'Engle, a newspaper muckraker and U.S. House Representative.
With his eldest son Francis, also a lawyer, John L'Engle founded L'Engle and Son. L'Engle involved Francis in his business deals, and kept notes on Francis' many business transactions.
L'Engle kept sporadic accounts on food, and, less often, on household goods he purchased. He wrote more detailed notes on larger transactions and what he owed and was owed, often trading in bonds, notes, and sometimes railroad bonds. As well as being a lawyer and businessman, L'Engle planted crops and owned property which he refers to as "2 lots" and "100 acres." In addition he bought and sold many properties.