- Schmidts Island
- Scott
- Scranton
- Second Island
- Seven Sisters Islands
- Sexton Island
- Sheen Island
- Sheep Islands
- Shelland Island
- Shermans Corner
- Sherwood
- Shipman Island
- Shipwreck Island
- Silica
- Simar
- Sioux Pine Island
- Skibo
- Smith Island
- Smithville
- Smolich Island
- Snake Island
- Snake Island
- Snellman Island
- Snowden
- Sparta
- Sphunge Islands
- Spider Island
- Spirit Island
- Spruce
- Spruce Shadows Mobile Home Park