State Route 129 is an east–west highway in southwest Ohio running from its western terminus at the Indiana/Ohio state line near Scipio, Ohio at State Road 252, which continues west, and State Route 126, which continues southeast. Its eastern terminus is at I-75 in Liberty Township. The route's eastern terminus was historically at State Route 747 until 1999 when the route was moved south ½ mile to the newly built Butler County Veterans Highway.

Butler County Veterans Highway is signed as State Route 129 and is a limited access highway from Hamilton to its terminus at Interstate 75. The highway was conceived in the early 1970s as a link to Interstate 75 from Hamilton. At the time, Hamilton was the second largest city in the US without a direct connection to an Interstate. The highway has had three names. The original name was the Butler County Regional Highway. Shortly after the highway was built, the highway was renamed the Michael A. Fox Highway. In 2004 the highway was renamed to the Butler County Veterans Highway.

The entire route is in Butler County.