10 ILCS 5/8-5
There shall be constituted one legislative committee for each political party in each legislative district and one representative committee for each political party in each representative district. Legislative and representative committees shall be composed as follows:
In legislative or representative districts within or including a portion of any county containing 2,000,000 or more inhabitants, the legislative or representative committee of a political party shall consist of the committeepersons of such party representing each township or ward of such county any portion of which township or ward is included within such legislative or representative district and the chair of each county central committee of such party of any county containing less than 2,000,000 inhabitants any portion of which county is included within such legislative or representative district.
In the remainder of the State, the legislative or representative committee of a political party shall consist of the chair of each county central committee of such party, any portion of which county is included within such legislative or representative district; but if a legislative or representative district comprises only one county, or part of a county, its legislative or representative committee shall consist of the chair of the county central committee and 2 members of the county central committee appointed by the chair of the county central committee.
Within 180 days after the primary of the even-numbered year immediately following the decennial redistricting required by Section 3 of Article IV of the Illinois Constitution of 1970, the ward committeepersons, township committeepersons or chairmen of county central committees within each of the redistricted legislative and representative districts shall meet and proceed to organize by electing from among their own number a chair and, either from among their own number or otherwise, such other officers as they may deem necessary or expedient. The ward committeepersons, township committeepersons or chairmen of county central committees shall determine the time and place (which shall be in the limits of such district) of such meeting. Immediately upon completion of organization, the chair shall forward to the State Board of Elections the names and addresses of the chair and secretary of the committee. A vacancy shall occur when a member dies, resigns or ceases to reside in the county, township or ward which he represented.
Within 180 days after the primary of each other even-numbered year, each legislative committee and representative committee shall meet and proceed to organize by electing from among its own number a chair, and either from its own number or otherwise, such other officers as each committee may deem necessary or expedient. Immediately upon completion of organization, the chair shall forward to the State Board of Elections, the names and addresses of the chair and secretary of the committee. The outgoing chair of such committee shall notify the members of the time and place (which shall be in the limits of such district) of such meeting. A vacancy shall occur when a member dies, resigns, or ceases to reside in the county, township or ward, which he represented.
If any change is made in the boundaries of any precinct, township or ward, the committeeperson previously elected therefrom shall continue to serve, as if no boundary change had occurred, for the purpose of acting as a member of a legislative or representative committee until his successor is elected or appointed.
10 ILCS 5/8-5