Running concurrently with U.S. Route 31E for its first 8.607 miles (13.852 km) in Kentucky, US 231/31E enters the state from Sumner County, Tennessee, and into Allen County. The two routes separate on the west side of Scottsville after the KY 100 junction. US 231 turns northwestward onto a four-lane highway on its way into Warren County, and into Bowling Green. Just before entering the city, US 231 crosses the southern terminus of KY 9007, a short connector providing access to I-65 and I-165. US 231 crosses I-65 in the Greenwood neighborhood of Bowling Green, US 31W and US 68 within city limits, and I-165 on the northwestern edge of the city.[2]
US 231 reaches Butler County to cross I-165 for a second time, and runs concurrently with KY 79 on the southern end of Morgantown. On the northern end of Morgantown, KY 70 joins in on the concurrency as US 231, KY 79, and KY 70 cross the Green River. Both state routes separate from US 231 in the Aberdeen area before crossing the I-165 for a third time before entering Ohio County. US 231 meets U.S. Route 62 in the Beaver Dam/Hartford area after crossing the Wendell H. FordWestern Kentucky Parkway on the south side of Beaver Dam.[3]
In Kentucky, US 231 was originally signed as Kentucky Route 71, one of many charter routes of Kentucky's statewide system of highways when it was established in 1929.[5] KY 71 originally ran from downtown Scottsville to downtown Owensboro. Prior to 1936, KY 71 followed the present-day KY 403 from Morgantown to Cromwell via Logansport and a ferry crossing.[6] In 1936, KY 71 was rerouted to Aberdeen in order to accommodate the alignment KY 70 and KY 105 (now KY 79) via another ferry crossing between Morgantown and Aberdeen.[7] A bridge over the Green River between the two cities opened around 1952, replacing the Morgantown-Aberdeen Ferry. In 1952, US 231 replaced the designation of KY 71 in its entirety as the U.S. route was extended from Montgomery, Alabama into Kentucky and Indiana via Huntsville, Alabama and Murfreesboro, Tennessee.[8][9] US 231 also replaced parts of KY 75's course through downtown Owensboro, including its final stretch onto the Owensboro Bridge into Indiana.
Modern-day realignments (1990-present)
In August 1999, US 231 in Bowling Green was rerouted onto KY 880 (Campbell Lane) from the Scottsville Road intersection to the Morgantown Road intersection on the northwest side of town. The former alignment of US 231 into downtown Bowling Green was redesignated as U.S. 231 Business.
The stretch of US 231 from the Natcher Parkway (now I-165) interchange to Bell Street in Morgantown was widened to include a center lane for left-turning in 2013–2014.[12][13][14]
Scottsville Road speed limit increase
In late May 2017, the KYTC raised the speed limit of US 231 from near Scottsville to the near the Drakes Creek bridge south of Bowling Green from the original 55 miles per hour (89 km/h) to 65 miles per hour (105 km/h).[15] This makes this stretch of US 231 the second section of a four-lane divided highway with unlimited access in the region with a 65 mph speed limit, the first being US 68/KY 80 from I-24 in Trigg County to the Natcher Parkway Exit 7 (now I-165 Exit 5) interchange at Bowling Green.
^French, Jackson (May 23, 2017). “State increases speed limit to 65 mph on U.S. 231.” Bowling Green Daily News, May 23, 2017, pages 1A and 6A. Retrieved May 25, 2017.
US 231 / US 31E at the Tennessee state line near Adolphus
