| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Sebastiao Caixao | city | Piaui | Brazil | -6.37 | -40.83 | 2011 | 74 |
| Segredo | city | Piaui | Brazil | -4.95 | -41.55 | 830 | 745 |
| Sem Denominação | city | Piaui | Brazil | -5.06 | -42.77 | 360 | 205254 |
| Sem Rival | city | Piaui | Brazil | -6.63 | -41.25 | 1669 | 206 |
| Serieme | city | Piaui | Brazil | -6.15 | -42.52 | 830 | 1064 |
| Seringa | city | Piaui | Brazil | -3.48 | -42.51 | 39 | 14260 |
| Serra | city | Piaui | Brazil | -7.25 | -41.60 | 830 | 2968 |
| Serra | city | Piaui | Brazil | -7.77 | -41.27 | 1010 | 450 |
| Serra Negra | city | Piaui | Brazil | -4.08 | -41.68 | 830 | 632 |
| Serra Negra | city | Piaui | Brazil | -5.90 | -42.32 | 830 | 695 |
| Serra Nova | city | Piaui | Brazil | -8.98 | -42.87 | 1732 | 604 |
| Serra Vermeiha | city | Piaui | Brazil | -5.45 | -40.03 | 1961 | 665 |
| Serra Vermelha | city | Piaui | Brazil | -7.83 | -44.17 | 1099 | 147 |
| Serra Vermelha | city | Piaui | Brazil | -7.93 | -40.90 | 1669 | 1015 |
| Serra do Jacaranda | city | Piaui | Brazil | -5.87 | -42.78 | 1020 | 618 |
| Serra do Joaozinho do Mestre Pedro | city | Piaui | Brazil | -6.27 | -40.85 | 2631 | 152 |
| Serra do Raimundo Bernardo | city | Piaui | Brazil | -6.27 | -40.83 | 2509 | 234 |
| Serra do Sobrado | city | Piaui | Brazil | -7.82 | -41.22 | 1118 | 447 |
| Serra do Sobrodo | city | Piaui | Brazil | -7.82 | -41.22 | 1118 | 447 |
| Serra do Valente | city | Piaui | Brazil | -5.88 | -41.63 | 830 | 6 |
| Serra dos Matoes | city | Piaui | Brazil | -4.38 | -41.43 | 2014 | 18712 |
| Serragem | city | Piaui | Brazil | -3.62 | -42.58 | 75 | 2939 |
| Serrinha | city | Piaui | Brazil | -5.25 | -41.37 | 1000 | 226 |
| Serrinha | city | Piaui | Brazil | -6.92 | -40.92 | 1669 | 1952 |
| Serrinha | city | Piaui | Brazil | -5.60 | -41.33 | 1669 | 0 |
| Serrinha | city | Piaui | Brazil | -5.73 | -41.05 | 2509 | 596 |
| Sertao de Dentro | city | Piaui | Brazil | -4.30 | -41.68 | 1020 | 4271 |
| Sertãozinho | city | Piaui | Brazil | -8.11 | -41.64 | 1200 | 596 |
| Sete Lagoas | city | Piaui | Brazil | -9.20 | -45.48 | 1965 | 53 |
| Sete Lagoas | city | Piaui | Brazil | -9.57 | -44.10 | 1998 | 316 |
| Sete Lagoas | city | Piaui | Brazil | -8.45 | -41.70 | 1669 | 447 |