Clifton was officially annexed by Louisville in 1891, though portions of it were developed long before. The earliest structure known to exist in Clifton was built around 1820. The oldest structure that is still standing (2311 Frankfort Ave, formerly the Tollhouse) was built in 1830.
Frankfort Avenue Caron's City Directory information and Sanborn maps - 1884, 1892, 1905, 1928
1865 Clifton map showing Ft Elstner