55 ILCS 125/10

The original field notes of the United States surveys and copies thereof, and all papers and documents pertaining thereto shall be transferred by the Auditor of Public Accounts to the custody of the Secretary of State. The Secretary of State shall deposit such field notes and the documents and records pertaining thereto in the State Archives for safe-keeping. Copies of such notes, records and documents made and certified by the Secretary of State, under his official seal, shall be competent evidence in all courts of this State.