55 ILCS 5/3-6030: Vacancy; power of deputies.

In case of a vacancy in the office of sheriff, every deputy in office under him or her having a process in his or her possession at the time such vacancy happens, shall have the same authority and be under the same obligation to serve, execute and return the same as if the sheriff had continued in office.

Any vacancy occurring in the office of sheriff shall be filled as provided in The Election Code.

In counties of over 2,000,000 inhabitants, until a vacancy in the office of sheriff is filled as provided in The Election Code, the undersheriff shall be the acting sheriff with all the powers and duties of a sheriff.