The head of the Illinois Republican Party says Tom Cross ran a "tough, hard-fought'' race against Democrat Mike Frerichs.
Cross conceded the close contest Wednesday, saying he called the Democratic state senator to congratulate him.
Cross is a longtime legislator who served as minority leader of the Illinois House.
In a statement, state GOP Chairman Tim Schneider says Cross provided more than two decades of "principled leadership.''
Frerichs will replace Republican Treasurer Dan Rutherford, who didn't seek re-election so he could run for governor. He lost in the four-way GOP primary.
That leaves Comptroller Judy Baar Topinka as the remaining Republican constitutional officer to serve with Republicans, Gov.-elect Bruce Rauner and Lt. Gov.-elect Evelyn Sanguinetti.
Rauner takes office in January. He ousted Democratic Gov. Pat Quinn on Nov. 4.
