John Mattingly was a slave dealer, mostly in St. Louis and also in Louisville, Kentucky. The abolitionist Thomas Wentworth Higginson visited St. Louis in 1856 to make an investigation of the slave trade and mentioned Mattingly (see below). Higginson visited the Corbin Thompson slave pen during his visit, likely the same one mentioned in Mattingly’s advertisement of April 15, 1859, in the Daily Missouri Republican: “…I will pay…more money than any trader in the City of St. Louis or the State of Missouri…I can be found at the City Hotel, or Corbin Thompson’s Negro Yard at No.3 Sixth street, one square south of the County jail. John Mattingly.” Another Republican advertisement dated October 28, 1859, revealed that Mattingly had two agents in other Missouri towns: James M. Hunter in Independence and William Stewart in Palmyra. Several of Mattingly’s 1859 advertisements mention that he was procuring slaves for a plantation in Louisiana.