Save This Event For Later National 24-Hour Challenge - N24HC Middleville, MI, Sat Jun 17 - Sun Jun 18, 2017 Contact Event | Event Website | Google Calendar Start line address: 10375 Green Lake Rd, Middleville, MI 49333 Presented by National 24-Hour Challenge, Inc. This is a past event. If you wish to see the details for this past event click "Continue" below. If you are looking for a current event, please search the event calendar .