Kentucky Route 603 is a 1.701-mile-long (2.737 km) supplemental road in Owensboro in central Daviess County.

The highway crosses over the parkway before reaching its north end at an acute intersection with US 62 (Everly Brothers Boulevard).

Kentucky Route 607 is a 17.421-mile-long (28.036 km) rural secondary highway in southern Owen County.

KY 607 heads east along New Columbus Road, which immediately crosses Cedar Creek and has a hairpin at New.

The route intersects KY 227 (Georgetown Road) west of Fairbanks, east of which the highway crosses Caney Creek.

The highway continues through New Columbus to its eastern terminus at KY 330 (Owenton Road) at the Owen–Grant county line.

Kentucky Route 623 is a 6.087-mile-long (9.796 km) rural secondary highway in southwestern Spencer County.

The highway begins at KY 48 (Highgrove Road) just north of the East Fork of Cox Creek, which forms the Spencer–Nelson county line.

The highway crosses Flat Rock Branch of Muddy Creek and intersects KY 79 (Russellville Road) at Davis Crossroads.

The highway crosses the Butler–Warren county line and continues east on Jackson Bridge Road.

The highway reaches its eastern terminus at KY 1435 (Barren River Road) at Rockland.

Kentucky Route 633 is a 1.689-mile-long (2.718 km) supplemental state highway in far northwestern Adair County that runs from Cane Valley Road at the Taylor County line to Kentucky Route 55 and Cane Valley Church Road south of Coburg.

The highway begins at KY 248 (Briar Ridge Road) east of Taylorsville Lake.

KY 636 heads north along Van Buren Road, which crosses Little Beech Creek on its way to Mount Eden, which sits on the Spencer–Shelby county line.

The highway passes through Junte before reaching its northern terminus at KY 395 (Waddy Road) west of Harrisonville.

Kentucky Route 640 is a 16.723-mile-long (26.913 km) rural secondary highway in western Metcalfe County.

The highway curves west and crossing Falling Timber Creek and meets the eastern end of KY 1330 (Kino Road) very close to the Metcalfe–Barren county line.

Kentucky Route 649 is a 3.630-mile-long (5.842 km) state highway in northern Elliott County that runs from Kentucky Route 504 east of Ault to Mobley Flats Road and Ibex Post Office Road northeast of Ibex via Beartown and Stark.

Kentucky Route 654 is a 8.262-mile-long (13.296 km) rural secondary state highway in eastern Crittenden County that runs from Kentucky Route 120 at Tribune to Baker Hollow Road and Weston Road northwest of Mattoon via Mattoon.

Kentucky Route 655 is a 9.214-mile-long (14.828 km) rural secondary highway in western Edmonson County.

Kentucky Route 669 is a 3.078-mile-long (4.954 km) supplemental state highway in eastern Union County that runs from a point along East Market Street near St. Peter's Catholic Church in southeastern Waverly to Locust Lane and Yancy Greenwell Road southeast of Hitesville via Waverly.

Kentucky Route 678 is a 23.026-mile-long (37.057 km) rural secondary highway in western and northern Monroe County.

The highway continues along Stringtown Flippin Road, which follows Indian Creek to KY 2468 (Mud Lick Flippin Road) before veering north to cross Peter Creek west of Jeffrey.

Kentucky Route 679 is a 3.081-mile-long (4.958 km) supplemental and rural secondary state highway in far eastern McCreary County and far western Whitley that runs from a point along New Liberty Road 0.5-mile (0.80 km) west of Bear Wallow School Road to Kentucky Route 478 at Duckrun.

Kentucky Route 681 is a 2.828-mile-long (4.551 km) supplemental state highway in northwestern Fleming County that runs from Buchanan Road on the Nicholas County line to Kentucky Route 32 west of Cowan.

Kentucky Route 685 is a 13.040-mile-long (20.986 km) rural secondary highway in western Barren County.

Kentucky Route 688 was a 5.2-mile-long (8.4 km) rural secondary state highway in Crittenden County.

Kentucky Route 691 is a 7.802-mile-long (12.556 km) rural secondary state highway in central Cumberland County that runs from a dead end southwest of Ellington to Kentucky Route 90 west of Burkesville via Arat and Leslie.

Kentucky Route 694 was a state highway designated on October 27, 1993, running from KY 1/7 in Grayson northwest 5.790 miles (9.318 km).

The road became part of rerouted KY 9 on October 13, 1994, as the remaining sections of the AA Highway was being constructed.