Illinois Statutes Chapter 615. Waterways § 35/2. Claims affecting State's title to land

§ 2. No claim, other than that of the State, to any of the lands and premises, shall be recognized by the Department of Natural Resources or by any other officer of the State, except in cases where such claim is based upon the valid deed, contract, lease or permit of the proper officers of the State. It shall be the duty of the Department of Natural Resources to protect the rights of the State against any one who may have improperly seized or occupied any of the lands or premises and to that end it may employ any and all means which may be lawfully used in protecting the property of the State.