A special election was held to fill the remainder of the unexpired term for Illinois's 13th congressional district, which had vacated by Republican Donald Rumsfeld when he had been appointed Director of the Office of Economic Opportunity.

[1] In 1968, Illinois voters approved a call for a constitutional convention.

[1] The elections were nonpartisan, and primaries were only held in districts where enough candidates were running that a primary was required to be held to narrow them down for the general.

[1] A special election was held for the 53rd district seat of the Illinois Senate left vacant after Paul Simon resigned to assume the office of lieutenant governor of Illinois.

[1] A special election was held 33rd district seat of the Illinois House of Representatives left vacant after the death of John "Jack" B.