U.S. Federal Route 34 runs east-west across Union County. It is the main east-west highway in the county. This runs along the BNSF Railway. U.S. Rt. 34 passes through the following towns in Union County. Thayer Afton Creston
U.S. Rt. 34 is multi-plexed in Union County. U.S. Rt. 169, from near Thayer to Afton.
WB U.S. Rt. 34 at the Clark/Union County Line. WB U.S. Rt. 34/SB U.S. Rt. 169 near Grand River. WB U.S. Rt. 34/SB U.S. Rt. 169 east of Afton. WB U.S. Rt. 34 west of Afton. WB U.S. Rt. 34 east of Creston. WB U.S. Rt. 34 at Creston. WB U.S. Rt. 34/SB IA St Rt 25 in Creston. WB U.S. Rt. 34/SB IA St Rt 25 west of Creston.