55 ILCS 5/3-2011
Whenever a vacancy occurs in the office of any county clerk and the unexpired term exceeds one year, the vacancy shall be filled as provided by The Election Code by appointment of a clerk pro tempore, who shall qualify by giving bond and taking the oath as required of the county clerk, and shall thereupon perform all the duties and be entitled to all the emoluments and be subject to all the penalties appertaining to the office of county clerk until the successor of such clerk is elected or appointed and qualified; Provided, that in case the county clerk is called into the active military service of the United States, the appointee shall perform and discharge all the duties of the county clerk during the time such county clerk is in the active military service of the United States, and such county clerk so appointed shall possess all the powers and discharge all the duties of a regularly elected county clerk under the laws of this State, and shall be paid the same compensation as provided by law for the county clerk of that county, apportioned as to the time of service, and such appointment and all authority thereunder shall cease upon the discharge of the said county clerk from such active military service of the United States; and provided further, that the office of county clerk shall not be deemed to be vacant during the time the said county clerk is in the active military service of the United States.
55 ILCS 5/3-2011