Maryland Code, Commercial Law § 11-306

(a) A party to a marketing agreement may not raise any defense set out in § 11-305 of this subtitle unless he gives written notice to the other party of his intent to terminate or cancel the agreement. This notice shall be given in person or by registered or certified mail at least 60 days before the date on which he intends to terminate or cancel it.

(b) The 60-day notice is not required if at the time of termination or cancellation of the marketing agreement any of the following is proven:

(c) If notice is given by registered or certified mail, it shall be effective on the date of mailing.