Subject
Sleeping Bear Dunes National Lakeshore (Mich.)
30
Trails
15
Hiking
11
Cross-country skiing
8
National parks and reserves Management
4
Wilderness areas
4
Camp sites, facilities, etc
1
Camps
1
National parks and reserves
1
National parks and reserves Planning
1
Nature study
1
North Manitou Island (Mich.)
1
North Manitou Island (Mich.) Management
1
Outdoor recreation
1
Recreation areas
1
Sand dunes
1
Sleeping Bear Dunes National Lakeshore (Mich.) Management
1
Water resources development
1
Water-supply
1