Preamble
Adopted by Convention, August 31, 1847. Ratified by popular vote, March 6, 1848. In force April 1, 1848.
We, the people of the state of Illinois-grateful to Almighty God for the civil, political and religious liberty which He hath so long permitted us to enjoy, and looking to him for a blessing upon our endeavors to secure and transmit the same unimpaired to succeeding generations-in order to form a more perfect government, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this constitution for the state of Illinois.
Article I. Boundaries
§ 1. The boundaries and jurisdiction of the state shall be as follows, to-wit: Beginning at the mouth of the "Wabash river; thence up the same. and with the line of Indiana, to the northwest corner of said state; thence east, with the line of the same state, to the middle of lake Michigan; thence north along the middle of said lake, to north latitude 42° 30'; thence west to the middle of the Mississippi river, and thence down along the middle of that river to its confluence with the Ohio river; and thence up the latter river, along its northwestern shore, to the place of beginning: Provided, that this state shall exercise such jurisdiction upon the Ohio river as she is now entitled to, or such as may be agreed upon by this state and the state of Kentucky.
Article II. Concerning the Distribution of the Powers of Government
§ 1. The powers of the government of the state of Illinois shall be divided into three distinct departments, and each of them be confided to a separate body of magistracy, to-wit: Those which are legislative, to one; those which are executive, to another, and those which are judicial, to another.
§ 2. No person, or collection of person, being one of these departments. shall exercise any power properly belonging to either of the others, except as hereinafter expressly directed or permitted, and all acts in contravention of this section shall be void.
Article III. Of the Legislative Department
§ 1. The legislative authority of this state shall be vested in a general assembly, which shall consist of a senate and house of representatives, both to be elected by the people.
§ 2. The first election for senators and representatives shall be held on the Tuesday after the first Monday in November, 1848; and thereafter, elections for members of the general assembly shall be held once in two years, on the Tuesday next after the first Monday in November, in each and every county, at such places therein as may be provided by law.
§ 3. No person shall be a representative who shall not have attained the age of 25 years, who shall not be a citizen of the United States, and three years an inhabitant of his state, who shall have not resided within the limits of the county or district in which he shall be chosen 12 months next preceding his election, if such county or district shall have; been so long erected, but if not, then within the limits of the county or counties, district or districts, out of which the same shall have been taken, unless he shall have been absent on the public business of the United States or of this state, and who, moreover, shall not have paid a state or county tax.
§ 4. No person shall be a senator who shall not have attained the age of 30 years; who shall not be a citizen of the United States, five years an inhabitant of this state, and one year in the county or district in which he shall be chosen immediately preceding his election, if such county or district shall have been so long erected; but if not, then within the limits of the county or counties, district or districts, out of which the same shall have been taken, unless he shall have been absent on the public business of the United States, or of this state and shall not, moreover, have paid a state or county tax.
§ 5. The senators at their first session herein provided for shall be divided by lot, as near as can be, into two classes. The seats of the first class shall be vacated at the expiration of the second year, and those of the second class at the expiration of the fourth year, so that one-half thereof, as near as possible, may be biennially chosen forever thereafter.