The highway connects mostly rural areas of Graves County with the Tennessee state line and Mayfield.

KY 303 begins at the Tennessee state line, at an intersection with Foyshack Road, southeast of Pilot Oak, within Graves County.

The highway intersects the western terminus of KY 1890 just before it crosses over Perry Creek.

It intersects the western terminus of KY 80 and crosses over Kess Creek before passing Highland Park Cemetery.

The highway continues to the north and meets its northern terminus, an intersection with KY 121 Bus.