| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| S.S. de los Reyes | city | Madrid | Spain | 40.55 | -3.63 | 2509 | 227082 |
| SS de los Reyes | city | Madrid | Spain | 40.55 | -3.63 | 2509 | 227082 |
| San Agustin de Guadalix | city | Madrid | Spain | 40.68 | -3.61 | 2017 | 23712 |
| San Agustin del Guadalix | city | Madrid | Spain | 40.68 | -3.61 | 2017 | 23712 |
| San Agustín | city | Madrid | Spain | 40.68 | -3.61 | 2017 | 23712 |
| San Fernando de Henares | city | Madrid | Spain | 40.42 | -3.53 | 1794 | 277675 |
| San Lorenzo | city | Madrid | Spain | 40.59 | -4.14 | 3349 | 15454 |
| San Lorenzo de El Escorial | city | Madrid | Spain | 40.59 | -4.14 | 3349 | 15454 |
| San Lorenzo del Escorial | city | Madrid | Spain | 40.59 | -4.14 | 3349 | 15454 |
| San Mamés | city | Madrid | Spain | 40.99 | -3.71 | 3523 | 957 |
| San Martin de Valdieglesias | city | Madrid | Spain | 40.36 | -4.40 | 2509 | 4947 |
| San Martín de Valdeiglesias | city | Madrid | Spain | 40.36 | -4.40 | 2509 | 4947 |
| San Martín de la Vega | city | Madrid | Spain | 40.21 | -3.57 | 1669 | 23323 |
| San Sebastian de los Rejesas | city | Madrid | Spain | 40.55 | -3.63 | 2509 | 227082 |
| San Sebastian de los Reyes | city | Madrid | Spain | 40.55 | -3.63 | 2509 | 227082 |
| San-Fernando de Henaro | city | Madrid | Spain | 40.42 | -3.53 | 1794 | 277675 |
| Sanchinarro | city | Madrid | Spain | 40.41 | -3.71 | 2093 | 459938 |
| Sanctus Sebastianus Regum | city | Madrid | Spain | 40.55 | -3.63 | 2509 | 227082 |
| Santa Maria de la Alameda | city | Madrid | Spain | 40.60 | -4.26 | 4189 | 945 |
| Santorcaz | city | Madrid | Spain | 40.47 | -3.23 | 2864 | 2530 |
| Serracines | city | Madrid | Spain | 40.62 | -3.40 | 2509 | 3490 |
| Serrada de la Fuente | city | Madrid | Spain | 40.99 | -3.53 | 3704 | 662 |
| Serranillos | city | Madrid | Spain | 40.20 | -3.88 | 2509 | 14831 |
| Serranillos del Valle | city | Madrid | Spain | 40.20 | -3.88 | 2509 | 14831 |
| Sevilla La Nueva | city | Madrid | Spain | 40.35 | -4.03 | 2083 | 13770 |
| Sieteiglesias | city | Madrid | Spain | 40.91 | -3.58 | 2929 | 1541 |
| Somosaguas | city | Madrid | Spain | 40.42 | -3.80 | 2509 | 316763 |
| Somosierra | city | Madrid | Spain | 41.13 | -3.58 | 5029 | 489 |
| Soto de Pajares | city | Madrid | Spain | 40.28 | -3.53 | 1732 | 20241 |
| Soto del Real | city | Madrid | Spain | 40.75 | -3.78 | 3349 | 11699 |