Route 242 passes to the east of Belle Prairie City before crossing into Wayne County.

[4] The highway enters Orel Township in Wayne County and intersects Interstate 64 in the unincorporated community of Mayberry.

Route 242 heads northwest from Mayberry before turning north toward Wayne City.

[5][6] A route between McLeansboro and Wayne City was marked on Illinois road maps in 1922.

[2] Route 142A was first numbered on the 1929 Illinois state highway map.