The Illinois General Assembly is the legislative branch of the government of the state of Illinois in the United States, created by the first state constitution adopted in 1818. It works beside the executive branch led by the state governor and the judicial branch led by the state supreme court. The Illinois General Assembly comprises the Illinois House of Representatives which serves as the lower chamber and the Illinois Senate which serves as the upper chamber. The Illinois House of Representatives is made of 118 representatives elected from individual legislative districts to two-year terms. The Illinois Senate is made of 59 senators. As the electoral boundaries for the General Assembly are changed following every decennial census, not all Senate districts are equal in size.
In order to avoid complete turnovers in Senate membership, not all districts elect senators simultaneously. Every Senate district elects its members to serve two four-year terms and one two-year term per decade. The placement of the two-year term in the decade varies from one district to another, with each district's terms defined as 2-4-4, 4-2-4, or 4-4-2.
The Illinois General Assembly convenes at the Illinois State Capitol in Springfield, Illinois. Its first official working day is the second Wednesday of January each year. Its primary duties are to pass bills into law, approve the state budget, confirm appointments to state departments and agencies, act on federal constitutional amendments, and propose constitutional amendments for Illinois. It also has the power to override gubernatorial vetoes through a three-fifths majority vote in each chamber.