Shortly after the entry into Edmonson County, it reaches the community of Rocky Hill, where it intersects KY 1339 (Apple Grove Road).

It widens to four lanes just before it intersects the Wendell H. Ford Western Kentucky Parkway at its exit 107 interchange and meets US 62 in downtown Leitchfield.

After crossing Rough River Lake into Breckinridge County, it has a junction with Kentucky Route 79.

In the beginning, KY 259 only ran from Hardinsburg to Rhodelia, in Breckinridge and western Meade Counties.

The then-KY 65 (during its concurrency with KY 70) in Edmonson County crossed the Green River by ferry until it was re-routed onto a bridge in the 1950s.

This was done in order to avoid confusion between it and the then-planned-and-under-construction Interstate 65 (I-65) in the Edmonson/Warren/Barren County area, and its entire course through west-central Kentucky, which was completed in 1967.

In early 2001, the KYTC began construction of a two-lane bypass corridor from Brownsville's southern outskirts to just north of Chalybeate, including the rerouting of KY 259 from Rhoda to Brownsville, along with the final stretch of KY 101 in the Rhoda area.