The route continues through Johnson, Martin and Lawrence counties to terminate at another junction with U.S. Highway 23 south of Catlettsburg in Boyd County.

The road continues 8 miles (13 km) to the Lawrence County line.

In Lawrence County, it passes KY-1 and KY-1185, which takes you to Yatesville Lake.

It then continues into downtown Louisa toward Inez and on to Prestonsburg.

Kentucky Route 3 Spur (KY 3 Spur) is a short 0.053-mile (85 m) spur of KY 3 in Louisa running northeast to the West Virginia border at the Tug Fork of the Big Sandy River, where it continues into that state as West Virginia Route 37.