Illinois State Route 78 is the north-south highway in Whiteside County. IL St Rt 78 passes through the following towns in Whiteside County. Prophetstown Morrison
Unionville IL St Rt 78 is multi-plexed in Whiteside County. U.S. Rt. 30, near Morrison.
NB IL St Rt 78 at the Whiteside/Henry County Line. SB IL St Rt 78 south of Interstate 88. A BGS on WB I-88/IL St Rt 110. A BGS on WB I-88/IL St Rt 110. A BGS on WB I-88/IL St Rt 110. A guide marker on WB U.S. Rt. 30. WB U.S. Rt. 30/NB IL St Rt 78 in Morrison. A junction marker on WB U.S. Rt. 30/NB IL St Rt 78.