Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Pierron | Populated Place | 159 | Bond | 38 46 48 N | 089 35 53 W |
| Pierron | Populated Place | 157 | Bond | 38 46 35 N | 089 31 13 W |
| Piersols Run | Stream | | Fulton | 40 33 07 N | 090 23 59 W |
| Pierson | Populated Place | 206 | Piatt | 39 47 53 N | 088 31 42 W |
| Pierson Park | Park | 195 | Kankakee | 41 06 47 N | 087 50 34 W |
| Pierson School (historical) | School | 126 | Saline | 37 40 25 N | 088 32 09 W |
| Pietrowski Playground Park | Park | 181 | Cook | 41 43 11 N | 087 32 17 W |
| Piety Hill | Summit | 189 | La Salle | 41 18 28 N | 089 04 45 W |
| Pig Creek | Stream | | Knox | 40 48 11 N | 090 14 05 W |
| Pig Ridge | Ridge | 142 | Wayne | 38 19 09 N | 088 22 43 W |
| Pig Ridge School (historical) | School | 144 | Hamilton | 38 00 23 N | 088 23 33 W |
| Pigeon (historical) | Populated Place | 166 | Jefferson | 38 23 42 N | 088 45 23 W |
| Pigeon Creek | Stream | | Iroquois | 40 35 36 N | 087 51 07 W |
| Pigeon Creek | Stream | | Jefferson | 38 22 14 N | 088 45 30 W |
| Pigeon Creek | Stream | | Marshall | 40 58 04 N | 089 25 28 W |
| Pigeon Creek | Stream | | Pike | 39 42 42 N | 091 15 51 W |
| Pigeon Creek | Stream | | Williamson | 37 43 09 N | 089 01 55 W |
| Pigeon Creek Cemetery | Cemetery | 133 | Williamson | 37 42 57 N | 089 02 08 W |
| Pigeon Creek Settling Basin | Basin | 142 | Pike | 39 43 29 N | 091 14 33 W |
| Pigeon Hill Park | Park | 216 | Kane | 41 46 19 N | 088 18 01 W |
| Pigeon Hollow | Valley | | Knox | 40 51 59 N | 090 06 36 W |
| Pigeon Roost Creek | Stream | | Alexander | 37 09 20 N | 089 21 10 W |
| Pike | Populated Place | 138 | Pike | 39 27 35 N | 091 02 06 W |
| Pike Cemetery | Cemetery | 213 | Livingston | 40 48 25 N | 088 46 32 W |
| Pike County | Civil | 220 | Pike | 39 36 00 N | 090 49 00 W |
| Pike County Conservation Area | Park | 196 | Pike | 39 40 42 N | 090 38 43 W |
| Pike County Infirmary (historical) | Locale | 229 | Pike | 39 35 00 N | 090 49 43 W |
| Pike Creek | Stream | | Bureau | 41 30 44 N | 089 20 23 W |
| Pike Creek | Stream | | Iroquois | 40 56 14 N | 087 48 40 W |
| Pike Creek | Stream | | Kankakee | 41 10 46 N | 087 37 56 W |
| Pike Creek | Stream | | Livingston | 40 51 55 N | 088 42 33 W |
| Pike Creek | Stream | | Menard | 40 08 59 N | 089 40 48 W |
| Pike Lake | Lake | 137 | Cass | 40 03 25 N | 090 11 02 W |
| Pike Marsh | Swamp | 223 | McHenry | 42 18 38 N | 088 13 18 W |
| Pike Marsh Day Use Area | Locale | 233 | McHenry | 42 18 37 N | 088 13 37 W |
| Pike Marsh Picnic Area | Locale | 225 | Lake | 42 27 13 N | 088 11 00 W |
| Pike Run | Stream | | Mercer | 41 08 49 N | 090 46 56 W |
| Pike School (historical) | School | 201 | Christian | 39 25 19 N | 089 10 35 W |
| Pike Station Public Access Area | Locale | 140 | Pike | 39 28 14 N | 091 03 16 W |
| Pikes Airport | Airport | 182 | La Salle | 41 18 48 N | 088 51 38 W |
| Pikes Peak School (historical) | School | 196 | Clark | 39 27 30 N | 087 45 30 W |
| Pilcher Cemetery | Cemetery | 173 | Fayette | 38 57 58 N | 088 58 05 W |
| Pilcher Creek | Stream | | Wayne | 38 27 44 N | 088 20 28 W |
| Pilcher Park | Park | 188 | Will | 41 32 08 N | 088 00 49 W |
| Pilcher School (historical) | School | 192 | Will | 41 38 14 N | 088 12 47 W |
| Piles Fork | Stream | | Jackson | 37 44 44 N | 089 11 17 W |
| Pilgrim Baptist Church | Church | 124 | St. Clair | 38 36 17 N | 090 09 28 W |
| Pilgrim Baptist Church | Church | 233 | Winnebago | 42 15 18 N | 089 07 00 W |
| Pilgrim Baptist Church (historical) | Church | 182 | Cook | 41 50 04 N | 087 37 17 W |
| Pilgrim Church of God in Christ | Church | 186 | Cook | 41 40 54 N | 087 37 20 W |
| Pilgrim Congregational Church | Church | 189 | Cook | 41 53 20 N | 087 47 15 W |
| Pilgrim Evangelistic School | School | 195 | Clark | 39 23 45 N | 087 41 39 W |
| Pilgrim Faith United Church | Church | 187 | Cook | 41 43 16 N | 087 44 52 W |
| Pilgrim Holiness Christian Church | Church | 204 | Coles | 39 29 41 N | 088 10 41 W |
| Pilgrim Holiness Church | Church | 147 | La Salle | 41 20 49 N | 088 51 35 W |
| Pilgrim Lutheran Church | Church | 182 | Cook | 41 57 36 N | 087 40 40 W |
| Pilgrim Lutheran School | School | 182 | Cook | 41 57 36 N | 087 40 40 W |
| Pilgrim Missionary Baptist Church | Church | 181 | Cook | 41 54 48 N | 087 38 49 W |
| Pilgrim Rest Baptist Church | Church | 139 | Jefferson | 38 18 17 N | 088 54 06 W |
| Pilgrim Rest Missionary Baptist Church | Church | 182 | Cook | 41 52 58 N | 087 40 29 W |
| Pilgrim Temple Christian Methodist Episcopal Church | Church | 125 | St. Clair | 38 36 24 N | 090 09 08 W |
| Piling Chapel | Church | 196 | Macon | 39 50 33 N | 088 58 31 W |
| Pillar of Fire Church | Church | 183 | Cook | 41 56 16 N | 087 39 26 W |
| Pillars of Jerusalem Missionary Baptist Church | Church | 183 | Cook | 41 44 38 N | 087 39 14 W |
| Pillars Rock Baptist Church | Church | 181 | Cook | 41 54 26 N | 087 38 17 W |
| Pillow Hill Airport | Airport | 248 | Henry | 42 26 50 N | 088 12 05 W |
| Pilot Center (historical) | Populated Place | 201 | Kankakee | 41 03 27 N | 088 04 33 W |
| Pilot Center Cemetery | Cemetery | 202 | Kankakee | 41 03 25 N | 088 04 31 W |
| Pilot Creek | Stream | | Knox | 41 07 07 N | 090 10 56 W |
| Pilot Grove | Woods | 249 | Knox | 41 05 15 N | 090 14 36 W |
| Pilot Grove | Woods | 304 | Stephenson | 42 17 47 N | 089 55 02 W |
| Pilot Grove (historical) | Woods | 214 | Edgar | 39 39 30 N | 087 48 50 W |
| Pilot Grove Cemetery | Cemetery | 199 | Hancock | 40 32 31 N | 091 05 27 W |
| Pilot Grove Cemetery | Cemetery | 211 | Vermilion | 39 53 05 N | 087 36 55 W |
| Pilot Grove School (historical) | School | 214 | Edgar | 39 39 33 N | 087 48 53 W |
| Pilot Grove School (historical) | School | 198 | Hancock | 40 32 26 N | 091 04 32 W |
| Pilot Grove School (historical) | School | 207 | McDonough | 40 26 16 N | 090 28 02 W |
| Pilot Grove United Brethren Church (historical) | Church | 207 | McDonough | 40 26 17 N | 090 28 34 W |
| Pilot Hill | Summit | 227 | Kankakee | 41 01 41 N | 088 02 19 W |
| Pilot Knob | Summit | 298 | Jo Daviess | 42 22 31 N | 090 25 09 W |
| Pilot Knob | Summit | 264 | Knox | 41 05 06 N | 090 14 49 W |
| Pilot Knob | Summit | 193 | Pike | 39 31 11 N | 090 35 18 W |
| Pilot Knob Cemetery | Cemetery | 155 | Washington | 38 13 12 N | 089 27 46 W |
| Pilot Knob Mine | Mine | 221 | Jo Daviess | 42 22 58 N | 090 25 05 W |
| Pilot Knob Townhall | Building | 152 | Washington | 38 16 25 N | 089 25 00 W |
| Pilot School (historical) | School | 226 | Vermilion | 40 13 35 N | 087 51 10 W |
| Pilsen (subdivision) | Populated Place | 182 | Cook | 41 51 27 N | 087 39 27 W |
| Pilsen Community Academy | School | 184 | Cook | 41 51 32 N | 087 39 45 W |
| Pilsen Station Chicago Post Office | Post Office | 182 | Cook | 41 51 22 N | 087 39 56 W |
| Pin Oak Baptist Church | Church | 172 | St. Clair | 38 37 20 N | 089 59 13 W |
| Pin Oak Church | Church | 128 | Wayne | 38 24 04 N | 088 30 41 W |
| Pin Oak Lake | Lake | 139 | Pike | 39 38 48 N | 091 13 01 W |
| Pin Oak Point | Cape | 158 | Henderson | 40 44 18 N | 091 05 44 W |
| Pin Oak Post Office (historical) | Post Office | 128 | Wayne | 38 24 00 N | 088 29 34 W |
| Pin Oak School (historical) | School | 208 | Adams | 39 46 17 N | 091 05 48 W |
| Pin Oak School (historical) | School | 177 | Bond | 38 56 09 N | 089 30 02 W |
| Pin Oak School (historical) | School | 174 | Madison | 38 47 44 N | 089 53 36 W |
| Pin Oak School (historical) | School | 161 | Mercer | 41 12 08 N | 091 02 03 W |
| Pin Oak School (historical) | School | 191 | Scott | 39 44 26 N | 090 27 55 W |
| Pin Oak School (historical) | School | 135 | Wayne | 38 24 32 N | 088 31 15 W |
| Pinckneyville | Populated Place | 132 | Perry | 38 04 49 N | 089 22 55 W |
| Pinckneyville Community Hospital | Hospital | 132 | Perry | 38 04 52 N | 089 23 00 W |
| Pinckneyville Elementary School | School | 132 | Perry | 38 04 47 N | 089 23 06 W |
| Pinckneyville High School | School | 123 | Perry | 38 04 42 N | 089 22 31 W |
| Pinckneyville Middle School | School | 118 | Perry | 38 04 43 N | 089 22 19 W |
| Pinckneyville Number 1 Election Precinct | Civil | 132 | Perry | 38 04 47 N | 089 23 06 W |
| Pinckneyville Number 2 Election Precinct | Civil | 123 | Perry | 38 02 19 N | 089 21 07 W |
| Pinckneyville Number 3 Election Precinct | Civil | 125 | Perry | 38 00 21 N | 089 24 45 W |
| Pinckneyville Number 4 Election Precinct | Civil | 151 | Perry | 38 03 47 N | 089 27 23 W |
| Pinckneyville Number 5 Election Precinct | Civil | 155 | Perry | 38 06 15 N | 089 27 37 W |