Opdyke is a census-designated place in the southeastern part of Jefferson County, Illinois, United States.

The nearby, earlier town of Lynchburg was largely abandoned and moved to Opdyke.

A part of the railroad investment in this area was funded by a mortgage of $4,525,000 by Calhoun & Opdyke of New York.

The original surveys of Illinois, made around 1800, show the Goshen Road passing through what is now the center of Opdyke in a north–south direction.

The railroad is no longer a significant factor in the existence of the village, which now fronts on Illinois Route 142.