- Shambo
- Shawmut
- Sheffield
- Shirley
- Shonkin
- Silesia
- Silver Star
- Simpson
- Sioux Pass
- Sixteen
- Snawmut
- Snider
- Sonnette
- Springdale
- Square Butte
- Stockett
- Stryker
- Suffolk
- Sula
- Sumatra
- Summit
- Swan Lake
- Sweet Grass
- Scout Island
- Shepherds Trailer Court
- Springwater Colony
- Soda Springs
- Spraklin Island
- Spurling
- Saddle Butte