The Sleeping Bear Dunes National Lakeshore shared this announcement regarding the shutdown. Short answer is that the trails are open, but everything with staff is closed.
During the shutdown of the federal government due to the lapse of appropriations, Sleeping Bear Dunes National Lakeshore (National Lakeshore) will remain as accessible as possible while still following all applicable laws and procedures.
The visitor center will be closed and there will be no NPS-provided visitor services at the National Lakeshore, including restrooms, trash collection, or facilities maintenance. Services at the Platte River Campground will be discontinued as well, including snow plowing, custodial, bathrooms, showers, electricity, check-in/check- out, and reservations. Trails will remain accessible to visitors, but trailhead parking lots will not be plowed and emergency and rescue services will be limited.
During the federal government shutdown, NPS social media and websites will not be monitored or updated and so may not reflect current conditions. All park programs will be canceled until operations resume, including the guided snowshoe hikes that had been scheduled during Christmas week and early January.
You can visit the Department of the Interior for updates & information on the shutdown, and they add that the National Park Service employs over 20,000 people in 418 national parks.
See out Ken’s photo from March of 2014 and many more in his ginormous Sleeping Bear Dunes National Lakeshore album and if you have gifts yet to get, check out his awesome calendars, prints & books at kenscottphotography.com!