Horace Thayer (1811 - c. 1874) was a New York based publisher and lithographer active in New York City and Buffalo, New York, during the middle part of the 19th century. Thayer's publications focused on travel guides, wall, and pocket maps - many of which were based on the works of other American cartographers including J. H. Colton and S. A. Mitchell. According to map historian Walter Ristow, J. H. Colton's older son, George Washington Colton, partnered with Thayer in the late 1850s and early 1860s, possibly in order to learn Thayer's lithography techniques. Certainly a number maps emerged bearing a "Thayer and Colton" imprint. At various points Thayer also published with other prominent publishers and printmakers, publishing as Kelloggs and Thayer (1846-1847), Ensigns and Thayer (1848), Ensign and Thayer (1849-1850), and Ensign, Thayer, and Company (1850-1851), Phelps and Watson (1859), and Thayer and Colton (1859-186?). Thayer seems to have moved frequently and had offices at 50 Ann Street, 156 William Street, and at 18 Beekman Street, all in New York City.