Kentucky Route 864 (KY 864) is a 16.339-mile-long (26.295 km) state highway located entirely in the Louisville metropolitan area of Jefferson County in north central Kentucky.

The highway begins as an urban secondary route from there to the junction with Interstate 265 (I-265, Gene Snyder Freeway).

KY 864 is locally known as Poplar Level Road when it turns to the north and northwest to Watterson Park and Poplar Hills neighborhoods before crossing I-264 (Henry Watterson Expressway).

KY 864 then continues northward into downtown Louisville, where it crosses Eastern Parkway, Broadway, and ends at the U.S. Route 31E (US 31E, Baxter Avenue) intersection with East Jefferson Street.

[4] The entire route is in Louisville, Jefferson County.