| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Sidmar | city | Maryland | United States | 39.55 | -77.26 | 830 | |
| Sierra Manor | city | Maryland | United States | 38.39 | -75.50 | 65 | |
| Silesia | city | Maryland | United States | 38.74 | -77.00 | 49 | |
| Sillery Bay | city | Maryland | United States | 39.10 | -76.46 | 3 | |
| Sillery Bay Forest | city | Maryland | United States | 39.10 | -76.47 | 3 | |
| Sillman Estates | city | Maryland | United States | 39.03 | -76.50 | 65 | |
| Silo Hill | city | Maryland | United States | 39.70 | -77.32 | 410 | |
| Siloam | city | Maryland | United States | 38.33 | -75.68 | 22 | |
| Silva-De-Amor | city | Maryland | United States | 39.15 | -76.73 | 200 | |
| Silver Acres | city | Maryland | United States | 39.59 | -76.15 | 295 | |
| Silver Crest | city | Maryland | United States | 39.27 | -77.17 | 830 | |
| Silver Fern Estates | city | Maryland | United States | 39.40 | -77.18 | 830 | |
| Silver Gate Village | city | Maryland | United States | 39.39 | -76.46 | 147 | |
| Silver Hill | city | Maryland | United States | 38.84 | -76.95 | 249 | |
| Silver Hill | city | Maryland | United States | 39.46 | -77.31 | 830 | |
| Silver Hill Farm | city | Maryland | United States | 39.38 | -76.49 | 147 | |
| Silver Hill Park | city | Maryland | United States | 38.84 | -76.95 | 249 | |
| Silver Hills | city | Maryland | United States | 39.68 | -77.04 | 830 | |
| Silver Lake Mobile Home Park | city | Maryland | United States | 38.34 | -75.14 | 6 | |
| Silver Manor | city | Maryland | United States | 39.31 | -76.46 | 3 | |
| Silver Maple Estates | city | Maryland | United States | 39.33 | -77.25 | 830 | |
| Silver Meadow | city | Maryland | United States | 39.39 | -76.49 | 157 | |
| Silver Rock | city | Maryland | United States | 39.08 | -77.13 | 347 | |
| Silver Run | city | Maryland | United States | 39.68 | -77.04 | 830 | |
| Silver Run | city | Maryland | United States | 38.34 | -75.65 | 19 | |
| Silver Run Estates | city | Maryland | United States | 39.65 | -77.09 | 830 | |
| Silver Sands | city | Maryland | United States | 39.15 | -76.55 | 3 | |
| Silver Spring | city | Maryland | United States | 38.99 | -77.03 | 321 | |
| Silver Spring Heights | city | Maryland | United States | 39.52 | -76.36 | 305 | |
| Silver Spring Park | city | Maryland | United States | 38.99 | -77.02 | 272 | |
| Silver Spring Station | city | Maryland | United States | 39.39 | -76.48 | 157 | |
| Silver Woods | city | Maryland | United States | 39.39 | -76.45 | 95 | |
| Silverbrook Farm | city | Maryland | United States | 39.40 | -76.81 | 830 | |
| Silvergate East | city | Maryland | United States | 39.39 | -76.48 | 144 | |
| Simmons Acres | city | Maryland | United States | 38.64 | -77.04 | 91 | |
| Simms Landing | city | Maryland | United States | 38.49 | -77.03 | 29 | |
| Simms Wharf | city | Maryland | United States | 38.33 | -75.73 | 16 | |
| Simpson Woods | city | Maryland | United States | 39.18 | -76.92 | 830 | |
| Simpsons Farm | city | Maryland | United States | 38.70 | -76.61 | 147 | |
| Simpsons Mill | city | Maryland | United States | 39.58 | -77.22 | 400 | |
| Simpsonville | city | Maryland | United States | 39.19 | -76.88 | 400 | |
| Sinepuxent | city | Maryland | United States | 38.31 | -75.15 | 9 | |
| Singer | city | Maryland | United States | 39.47 | -76.34 | 98 | |
| Singer Heights | city | Maryland | United States | 39.60 | -76.86 | 830 | |
| Singer Woods | city | Maryland | United States | 39.48 | -76.32 | 249 | |
| Singerly | city | Maryland | United States | 39.65 | -75.84 | 114 | |
| Sixmile House | city | Maryland | United States | 39.64 | -78.85 | 1112 |