Fifth Avenue in Attalla until reaching US 11. In downtown Attalla, the route shares a brief wrong-way concurrency with US 11. West of Attalla, US 431 again turns to the northwest. At Guntersville, it joins with Alabama State Route 79. Through downtown Guntersville the route is divided into two separate one-way streets; the northbound street is named Blount Avenue, and the southbound street is Gunter Avenue. At the northern edge of Guntersville, the split streets combine and the joint route crosses the Tennessee River via the George S. Houston Bridge, before US 431 splits off and again heads in a northwest direction. At Huntsville, US 431 passes over Monte Sano Mountain and through Huntsville's medical district before reaching Memorial Parkway; this portion of the route forms a portion of Governors Drive. At the Parkway, the route joins with U.S. Route 231; the combined routes then travel northward to the Tennessee state line. Tennessee A few miles north of the state line, in Fayetteville, US 231 and 431 split again, with 431 heading northwest in combination with State Route 50. In the town of Petersburg, the combined route briefly joins with State Route 129; the trio head a few miles northwest before SR-129 splits off to the west. From here, US 431/SR 50 travels through mountainous and largely undeveloped territory in south central Tennessee until arriving in Lewisburg. On the east side of Lewisburg, it joins with U.S. Route 31A; the combined routes form part of a bypass around the eastern side of Lewisburg. This portion is named Ellington Parkway, and it forms brief unions with State Routes 272 and 11, plus a longer-lasting combination with State Route 106. Meanwhile, SR 50 splits off to travel through downtown Lewisburg, rejoining US 431 on the north side of town. On the north side of Lewisburg, US 31A splits off, and then a few miles later SR-50 splits off, while US 431 and SR-106 jointly continue north. The route pair, variously known through this section as Lewisburg Pike or Franklin Pike, eventually passes underneath Interstate 65 to enter the town of Franklin. Continuing north, the route pair passes through the exclusive Nashville subdivision of Brentwood before entering Nashville proper. The route skirts the campus of Vanderbilt University before entering downtown Nashville from the southwest. Crossing under Interstate 40 (where SR-106 ends), the route follows Broadway to its intersection with Rosa L. Parks Boulevard.