Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Old Center School House | School | 17 | Washington | 41 10 20 N | 071 33 45 W |
| Old Colony House | Building | 6 | Newport | 41 29 26 N | 071 18 47 W |
| Old Congregational Church | Church | 93 | Providence | 41 50 03 N | 071 35 14 W |
| Old Country Road School | School | 75 | Providence | 41 52 59 N | 071 30 43 W |
| Old Exeter Poor Farm (historical) | Locale | 52 | Washington | 41 32 51 N | 071 31 47 W |
| Old Forge Burial Ground | Cemetery | 17 | Kent | 41 38 30 N | 071 26 53 W |
| Old Friends Burial Ground | Cemetery | 34 | Newport | 41 31 33 N | 071 23 01 W |
| Old Gardner Cemetery | Cemetery | 51 | Washington | 41 32 57 N | 071 31 50 W |
| Old Harbor | Harbor | -3 | Washington | 41 10 28 N | 071 33 23 W |
| Old Harbor (historical) | Locale | 0 | Washington | 41 10 25 N | 071 33 27 W |
| Old Harbor Historic District | Park | 10 | Washington | 41 10 20 N | 071 33 27 W |
| Old Harbor Landing | Populated Place | 5 | Washington | 41 09 58 N | 071 32 55 W |
| Old Harbor Point | Cape | -3 | Washington | 41 09 53 N | 071 32 39 W |
| Old Hickory Brook | Stream | | Kent | 41 40 28 N | 071 34 59 W |
| Old Howard Plot | Cemetery | 203 | Providence | 41 45 32 N | 071 43 11 W |
| Old Meetinghouse | Locale | 27 | Washington | 41 35 38 N | 071 29 24 W |
| Old Mill Creek | Stream | | Kent | 41 42 43 N | 071 21 58 W |
| Old Mountain Field | Park | 26 | Washington | 41 26 50 N | 071 29 13 W |
| Old Narragansett Episcopal Church | Church | 6 | Washington | 41 34 23 N | 071 26 55 W |
| Old Orchard Cove | Bay | 1 | Newport | 41 37 50 N | 071 13 56 W |
| Old Sabbatarian Meeting-House | Church | 12 | Washington | 41 24 00 N | 071 47 58 W |
| Old Salt Work Beach | Beach | 7 | Newport | 41 28 53 N | 071 21 36 W |
| Old Schoolhouse | School | 80 | Newport | 41 33 46 N | 071 15 15 W |
| Old Sergeant | Pillar | 1 | Washington | 41 32 03 N | 071 24 51 W |
| Old Sow Rock | Pillar | 1 | Washington | 41 37 11 N | 071 24 22 W |
| Old State House | Building | 16 | Providence | 41 49 43 N | 071 24 30 W |
| Old Stone Church | Church | 55 | Newport | 41 33 41 N | 071 08 35 W |
| Old Stone Mill | Locale | 25 | Newport | 41 29 09 N | 071 18 36 W |
| Old Washington County Courthouse | Building | 32 | Washington | 41 28 41 N | 071 33 02 W |
| Old Washington County Jail | Building | 74 | Washington | 41 28 45 N | 071 31 30 W |
| Old Whale Rock | Pillar | -3 | Washington | 41 09 26 N | 071 32 32 W |
| Oliphant School | School | 47 | Newport | 41 32 23 N | 071 17 25 W |
| OLiver Gardiner Cemetery | Cemetery | 60 | Washington | 41 30 11 N | 071 28 20 W |
| Oliver Hazard Perry Middle School | School | 37 | Providence | 41 49 52 N | 071 27 20 W |
| Oliver School | School | 23 | Bristol | 41 40 17 N | 071 16 19 W |
| Oliver Watson Farm (historical) | Locale | 53 | Washington | 41 29 16 N | 071 31 47 W |
| Oliver Watson House | Building | 53 | Washington | 41 29 16 N | 071 31 47 W |
| Olney Building | Building | 30 | Providence | 41 49 28 N | 071 24 06 W |
| Olney Margolies Building | Building | 41 | Providence | 41 49 52 N | 071 23 48 W |
| Olney Pond | Reservoir | 60 | Providence | 41 53 41 N | 071 25 36 W |
| Olney Pond Dam | Dam | 60 | Providence | 41 53 41 N | 071 25 36 W |
| Olney Street Baptist Church | Church | 42 | Providence | 41 50 08 N | 071 24 15 W |
| Olney Street-Alumni Avenue Historic District | Park | 55 | Providence | 41 50 08 N | 071 23 58 W |
| Olneys Tavern (historical) | Building | 24 | Providence | 41 50 07 N | 071 24 34 W |
| Olneyville | Populated Place | 13 | Providence | 41 48 53 N | 071 26 47 W |
| Olneyville Branch Providence Public Library | Building | 9 | Providence | 41 48 59 N | 071 26 36 W |
| Olneyville Post Office | Post Office | 7 | Providence | 41 48 57 N | 071 26 25 W |
| Omega (historical) | Populated Place | 10 | Providence | 41 50 06 N | 071 21 39 W |
| Omega Pond | Lake | 3 | Providence | 41 50 17 N | 071 21 53 W |
| Omega Pond Dam | Dam | 3 | Providence | 41 50 17 N | 071 21 53 W |
| One Hospital Trust Airport | Airport | 2 | Providence | 41 49 31 N | 071 24 36 W |
| One Mile Corner | Locale | 40 | Newport | 41 30 23 N | 071 18 07 W |
| Orchard Street School | School | 19 | Providence | 41 48 32 N | 071 22 23 W |
| Orlo Avenue School | School | 15 | Providence | 41 49 30 N | 071 21 51 W |
| Orwig Music Building | Building | 30 | Providence | 41 49 29 N | 071 23 40 W |
| Osamequin Nature Trails and Bird Sanctuary | Park | 2 | Bristol | 41 45 38 N | 071 19 16 W |
| Our Lady of Consolation Church | Church | 29 | Providence | 41 53 25 N | 071 22 19 W |
| Our Lady of Consolation School | School | 29 | Providence | 41 53 25 N | 071 22 15 W |
| Our Lady of Loreto School | School | 17 | Providence | 41 48 42 N | 071 21 54 W |
| Our Lady of Lourdes Church Complex | Church | 43 | Providence | 41 49 32 N | 071 26 49 W |
| Our Lady of Mercy Regional School | School | 27 | Kent | 41 39 13 N | 071 27 27 W |
| Our Lady of Mount Carmel Church | Church | 18 | Bristol | 41 40 30 N | 071 16 23 W |
| Our Lady of Mount Carmel Convent | Church | 18 | Bristol | 41 40 30 N | 071 16 23 W |
| Our Lady of Mount Carmel School | School | 18 | Bristol | 41 40 30 N | 071 16 23 W |
| Our Lady of Victories Regional Primary School | School | 61 | Providence | 42 00 32 N | 071 30 55 W |
| Our Lady of Victory Church | Church | 18 | Washington | 41 25 12 N | 071 47 21 W |
| Our Redeemer Lutheran Church | Church | 76 | Providence | 41 53 41 N | 071 32 26 W |
| Outreach Ministries | Church | 18 | Providence | 41 47 44 N | 071 25 28 W |
| Overbrook Academy | School | 41 | Kent | 41 40 48 N | 071 22 40 W |
| Overings Wharf (historical) | Locale | 0 | Newport | 41 28 42 N | 071 19 07 W |
| Owen Building | Building | 1 | Providence | 41 49 25 N | 071 24 28 W |
| Owls Nest Fort (historical) | Military (Historical) | 1 | Newport | 41 36 53 N | 071 13 16 W |
| Oxford Street School | School | 19 | Providence | 41 48 07 N | 071 24 34 W |
| Pacheco Park | Park | 80 | Providence | 42 00 02 N | 071 34 56 W |
| Pachet Brook | Stream | | Newport | 41 33 04 N | 071 11 47 W |
| Packard Rocks | Pillar | 13 | Washington | 41 31 03 N | 071 24 54 W |
| Packer State Fishing Access | Park | 35 | Washington | 41 27 48 N | 071 38 43 W |
| Page Island | Island | 136 | Providence | 41 56 05 N | 071 42 39 W |
| Paine Brook | Stream | | Providence | 41 48 17 N | 071 43 27 W |
| Palace Garden | Populated Place | 18 | Kent | 41 44 32 N | 071 24 03 W |
| Palmer Family Lot | Cemetery | 21 | Washington | 41 28 37 N | 071 43 43 W |
| Palmer River | Stream | | Bristol | 41 43 57 N | 071 17 20 W |
| Palmer-Burdick-Appley Lot | Cemetery | 123 | Washington | 41 32 41 N | 071 46 03 W |
| Pancake Island | Island | 0 | Providence | 41 49 16 N | 071 23 05 W |
| Paquantuck Brook | Stream | | Providence | 41 52 58 N | 071 45 08 W |
| Paradise Brook | Stream | | Newport | 41 29 28 N | 071 15 41 W |
| Paradise Mobile Home Park | Populated Place | 41 | Newport | 41 30 02 N | 071 16 41 W |
| Paradise Rocks | Pillar | 43 | Newport | 41 30 03 N | 071 15 44 W |
| Paradise School | School | 30 | Newport | 41 30 07 N | 071 16 06 W |
| Paradise Valley Park | Park | 30 | Newport | 41 30 06 N | 071 16 06 W |
| Park N Shop Center Shopping Center | Locale | 20 | Providence | 41 46 53 N | 071 26 25 W |
| Park School | School | 13 | Kent | 41 41 33 N | 071 25 03 W |
| Park Square Plaza Shopping Center | Locale | 99 | Providence | 41 58 55 N | 071 31 00 W |
| Park View Middle School | School | 13 | Providence | 41 46 29 N | 071 24 57 W |
| Parkis-Comstock Historic District | Park | 22 | Providence | 41 48 35 N | 071 25 15 W |
| Parmenter Brook | Stream | | Washington | 41 26 40 N | 071 47 45 W |
| Parris Brook | Stream | | Washington | 41 34 00 N | 071 42 53 W |
| Partridge Annex Building | Building | 40 | Providence | 41 49 39 N | 071 24 10 W |
| Partridge Building | Building | 39 | Providence | 41 49 38 N | 071 24 10 W |
| Pascoag | Populated Place | 130 | Providence | 41 57 20 N | 071 42 08 W |
| Pascoag Community Baptist Church | Church | 134 | Providence | 41 57 36 N | 071 42 31 W |
| Pascoag Public Library | Building | 139 | Providence | 41 57 24 N | 071 42 23 W |
| Pascoag Race Track (historical) | Park | 134 | Providence | 41 56 14 N | 071 41 03 W |
| Pascoag Reservoir | Reservoir | 131 | Providence | 41 57 02 N | 071 42 17 W |
| Pascoag Reservoir Upper Dam | Dam | 131 | Providence | 41 57 02 N | 071 42 17 W |
| Pascoag River | Stream | | Providence | 41 57 58 N | 071 42 01 W |
| Pasquiset Brook | Stream | | Washington | 41 26 52 N | 071 37 30 W |
| Pasquiset Pond | Lake | 25 | Washington | 41 25 32 N | 071 37 49 W |
| Passeonkquis Cove | Bay | 3 | Kent | 41 44 49 N | 071 23 06 W |
| Patience Island | Island | 16 | Newport | 41 39 24 N | 071 21 34 W |