The county covers an area of . As of 2006 its total population is 116,086, out of which the population of Otwock is 43,247, that of Józefów is 18,353, that of Karczew is 10,396, and the rural population is 44,090.
| Gmina | Type | Area (km²) | Population (2006) | Seat |
| Otwock | urban | 47.3 | 43,247 | |
| Józefów | urban | 23.9 | 18,353 | |
| Gmina Karczew | urban-rural | 81.5 | 15,919 | Karczew |
| Gmina Celestynów | rural | 88.9 | 11,032 | Celestynów |
| Gmina Wiązowna | rural | 102.1 | 9,890 | Wiązowna |
| Gmina Kołbiel | rural | 106.4 | 7,980 | Kołbiel |
| Gmina Sobienie-Jeziory | rural | 97.4 | 6,229 | Sobienie-Jeziory |
| Gmina Osieck | rural | 67.5 | 3,436 | Osieck |