Kentucky Route 400 is a 1.377-mile-long (2.216 km) supplemental road in the city of Oak Grove in southern Christian County.

The highway turns north away from the state line and veers east again to its terminus at KY 115 (Pembroke–Oak Grove Road).

The route was added as a rural secondary highway; however, the highway was reclassified as a supplemental road at an unknown date, returned to the rural secondary system through an October 26, 2004, official order, and returned to the supplemental road system after a December 9, 2010, official order.

Until March 1, 2021, there was a 0.874-mile-long (1.407 km) portion in Ohio County that was a supplemental road that ran from the Green River north to US 231 near Cromwell.

The highway begins at KY 66 at the Clay County line where Upper Jacks Creek empties into the Red Bird River.

The highway passes through Wheel and briefly runs concurrently with KY 339 between a bridge over Goose Creek and a grade crossing of a Canadian National rail line.

The western segment ofKY 408 intersects a Paducah & Louisville Railway line at Viola and crosses Mayfield Creek before reaching its eastern terminus at Hopewell Road.

KY 408 continues east on Oak Level Road, which crosses Middle Fork Creek, a tributary of Clarks River.

At Baxter, the highway meets the southern end of KY 3460 (Sukey Hill Road) and has a grade crossing of the CV Subdivision at the railroad's junction with its Poor Fork Branch, which the route continues along.

The highway passes under US 119 just west of its southern junction with US 421 and parallels the Poor Fork and the eponymous rail line northeast.

KY 413 intersects US 421 (Pine Mountain Road) just west of the U.S. Highway's northern junction with US 119, which runs along the opposite side of Poor Fork.

The highway continues northwest and crosses Smith Creek at Cannons Mill before reaching its northern terminus at KY 350.

North of the parkway in the village center, the highway turns east at its junction with KY 351 (Zion Road).

The highway crosses Lick Creek at Polin before reaching its northern terminus at KY 458 (Mount Zion Road).

KY 439 enters the Columbia Commercial Historic District and passes the Dr. Nathan Gaither House before ending as the north leg of a four-legged roundabout that encircles the Adair County Courthouse.

The highway intersects KY 408 west of Pottsville and crosses Wilson Creek as it approaches the village of Lowes.

KY 444 heads northeast along Dunbar Road, which crosses Beechy Creek and Tan Branch, both tributaries of the Blood River of Kentucky Lake.

KY 447, which follows Wilson Road, heads west and curves north at a tangent intersection with Cabinet Lane at the route's bridge across Shaw Creek, a tributary of the Nolin River.

At Providence, the highway curves east and meets the west end of KY 2423 (Sharps Gap Road).

The route heads east along Boone Road, which runs northeast between Lick Creek to the south and I-71 to the north.

KY 470 begins at a tangent intersection with US 31E (New Jackson Highway) in the village of Magnolia at the south end of LaRue County.

The highway briefly runs concurrently with US 60 in the city of Kevil, then the route turns northeast into McCracken County.

The highway passes through Monkeys Eyebrow and turns southwest along the edge of Ballard Wildlife Management Area, which lies between the route and the Ohio River.

The highway begins at KY 59 southeast of Camp Dix and immediately crosses Laurel Fork of Kinniconick Creek, a tributary of the Ohio River.

KY 478 continues along Whitley City Williamsburg Road, which has a curvaceous path through Daniel Boone National Forest.

The highway continues northwest on Grapevine Road, then the route turns west on McLaughlin Street for one block to its terminus at US 41 and KY 70.

The highway passes under the Hal Rogers Parkway then curves east, crosses over Little Sandy Creek, and reaches its northern terminus at KY 1305 (Tom Cat Trail).

[1][108][111][109][113] Kentucky Route 492 is a 11.014-mile-long (17.725 km) highway with rural secondary and supplemental road sections in western Union County.

KY 494 heads east and intersects a north–south CSX rail line before reaching its eastern terminus at US 41 south of Sebree.

KY 497 heads east on a curvaceous path that takes the route to its end at the barge terminal entrance on the west shore of Kentucky Lake.