Illinois Rules of Civil Procedure

Illinois Compiled Statutes 5 ILCS 50
Common Law Act. Section 1

(5 ILCS 50/1) (from Ch. 1, par. 801)
Sec. 1. That the common law of England, so far as the same is applicable and of a general nature, and all statutes or acts of the British parliament made in aid of, and to supply the defects of the common law, prior to the fourth year of James the First, excepting the second section of the sixth chapter of 43rd Elizabeth, the eighth chapter of 13th Elizabeth, and ninth chapter of 37th Henry Eighth, and which are of a general nature and not local to that kingdom, shall be the rule of decision, and shall be considered as of full force until repealed by legislative authority.

(Source: R.S. 1874, p. 269.)

http://law.onecle.com/illinois/5ilcs50/1.html

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Illinois Compiled Statutes 735 ILCS 5
Code of Civil Procedure. Section 8-1003

(735 ILCS 5/8-1003) (from Ch. 110, par. 8-1003)
Sec. 8-1003. Common law and statutes. Every court of this state shall take judicial notice of the common law and statutes of every state, territory and other jurisdiction of the United States.

(Source: P.A. 82-280.)

http://law.onecle.com/illinois/735ilcs5/8-1003.html