Mich. Comp. Laws § 120.1
Port districts are hereby authorized to be created in the various counties of this state, as in this act provided. Such districts whether heretofore or hereafter created, shall be bodies corporate and have a corporate seal, and may sue and be sued and may contract and be contracted with. Port districts shall have all the powers specifically granted to them and any powers implied or necessary for the exercise of the powers specifically granted. Whenever in this act any power is granted to a port district, it shall be exercised by the port commission unless otherwise provided herein, and whenever in this act any power is granted to a port commission it shall be deemed to be granted to the port district but to be exercised by such port commission.
MCL 120.1