Kentucky State Route 139 runs north-south across the center of Caldwell County. It runs from the tri-point of Trigg/Caldwell/Lyon County Line, near southeast of Lamasco to the Caldwell/Crittenden County Line, west of Marion. KY St Rt 139 passes through the following town in Caldwell County. Princeton
KY St Rt 139 is multi-plexed with the following highways in Caldwell County. Kentucky State Route 514, near Lamasco. Kentucky State Route 293, at Princeton.
Branches of KY St Rt 139 in Caldwell County. A BGS on NB I-69/EB WKY Pkwy. SB KY St Rt 91/139 south of NB I-69/EB WK Pkwy. A set of guide markers on SB KY St Rt 91/139. EB U.S. Rt. 62 SB KY St Rt 91/139 south of Seminary in Princeton. SB KY St Rt 139/293 near Washington in Princeton. A guide marker on NB TK KY St Rt 139/TK KY St Rt 239. EB U.S. Rt. 62; SB KY St Rt 91; NB KY St Rt 139/293 on the southeast side of the courthouse square.