Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Persimmon Point Camping Area | Locale | 159 | Jasper | 39 00 57 N | 088 07 13 W |
| Persimmon Ridge Picnic Area | Locale | 136 | Hamilton | 38 03 32 N | 088 24 06 W |
| Persinger Cemetery | Cemetery | 167 | Schuyler | 40 03 22 N | 090 33 52 W |
| Person Creek | Stream | | La Salle | 41 19 27 N | 088 43 23 W |
| Person School (historical) | School | 262 | DeKalb | 42 01 21 N | 088 40 37 W |
| Peru | Populated Place | 183 | La Salle | 41 19 39 N | 089 07 44 W |
| Peru Mall Shopping Centr | Locale | 197 | La Salle | 41 21 18 N | 089 07 40 W |
| Peru Post Office | Post Office | 177 | La Salle | 41 19 38 N | 089 07 31 W |
| Peru Public Library | Building | 184 | La Salle | 41 20 03 N | 089 07 28 W |
| Peru Turner Hall | Building | 184 | La Salle | 41 19 40 N | 089 07 50 W |
| Peru Washington School | School | 184 | La Salle | 41 19 58 N | 089 07 18 W |
| Pesotum | Populated Place | 218 | Champaign | 39 54 53 N | 088 16 24 W |
| Pesotum Cemetery | Cemetery | 216 | Champaign | 39 54 45 N | 088 16 10 W |
| Pesotum Grade School | School | 218 | Champaign | 39 54 58 N | 088 16 34 W |
| Pestalozzi-Froebel Teachers College | School | 182 | Cook | 41 53 08 N | 087 37 37 W |
| Pet Haven Cemetery | Cemetery | 220 | DuPage | 41 58 55 N | 088 01 29 W |
| Pete Vonachen Stadium | Park | 181 | Peoria | 40 42 35 N | 089 36 52 W |
| Peter and Paul School | School | 181 | Cook | 41 49 31 N | 087 40 02 W |
| Peter Cottontail Day Nursery | School | 181 | Cook | 41 50 11 N | 087 43 33 W |
| Peter Hoy School | School | 220 | DuPage | 41 52 10 N | 088 01 46 W |
| Peter J Palombi School | School | 244 | Lake | 42 24 42 N | 088 04 43 W |
| Peter Jans Golf Course | Locale | 184 | Cook | 42 04 05 N | 087 41 14 W |
| Peter Kroehler Memorial Dormitory | Building | 220 | DuPage | 41 46 33 N | 088 08 18 W |
| Peter Piper Nursery and Kindergarten | School | 181 | Cook | 41 47 09 N | 087 35 24 W |
| Peter Rock Mother Church | Church | 183 | Cook | 41 48 02 N | 087 37 32 W |
| Peters Cemetery | Cemetery | 204 | Champaign | 40 04 34 N | 088 01 29 W |
| Peters Cemetery | Cemetery | 165 | Madison | 38 43 47 N | 089 59 53 W |
| Peters Creek | Populated Place | 140 | Hardin | 37 29 16 N | 088 14 29 W |
| Peters Creek | Stream | | Hardin | 37 27 25 N | 088 15 34 W |
| Peters Creek Cemetery | Cemetery | 137 | Hardin | 37 29 32 N | 088 14 27 W |
| Peters Creek Lookout Tower | Tower | 252 | Hardin | 37 30 49 N | 088 14 14 W |
| Peters Creek School | School | 135 | Hardin | 37 29 31 N | 088 14 19 W |
| Peters Park | Park | 192 | Iroquois | 40 47 00 N | 087 43 42 W |
| Peters Rock Church of God in Christ | Church | 178 | Cook | 41 39 05 N | 087 36 13 W |
| Petersburg | Populated Place | 156 | Menard | 40 00 42 N | 089 50 53 W |
| Petersburg | Populated Place | 167 | St. Clair | 38 35 32 N | 089 55 16 W |
| Petersburg Airport | Airport | 186 | Menard | 40 01 21 N | 089 49 02 W |
| Petersburg East Number 13 Election Precinct | Civil | 183 | Menard | 39 59 49 N | 089 48 10 W |
| Petersburg Elementary School | School | 176 | Menard | 40 00 32 N | 089 51 17 W |
| Petersburg Foursquare Church | Church | 156 | Menard | 40 00 46 N | 089 50 56 W |
| Petersburg Historic District | Park | 157 | Menard | 40 00 40 N | 089 50 54 W |
| Petersburg North Number 14 Election Precinct | Civil | 176 | Menard | 40 01 58 N | 089 52 07 W |
| Petersburg South Number 15 Election Precinct | Civil | 185 | Menard | 39 59 20 N | 089 53 01 W |
| Petersburg United Methodist Church | Church | 165 | Menard | 40 00 37 N | 089 51 05 W |
| Petersburg West Number 16 Election Precinct | Civil | 164 | Menard | 40 00 44 N | 089 51 05 W |
| Petersen Cemetery | Cemetery | 237 | Pike | 39 40 47 N | 090 55 15 W |
| Peterson Cemetery | Cemetery | 178 | Bond | 38 56 03 N | 089 37 11 W |
| Peterson Cemetery | Cemetery | 172 | Johnson | 37 29 35 N | 088 57 55 W |
| Peterson Cemetery | Cemetery | 280 | Lee | 41 40 03 N | 089 14 24 W |
| Peterson Elementary School | School | 180 | Cook | 41 58 54 N | 087 42 46 W |
| Peterson Farms Airport | Airport | 190 | Kendall | 41 27 39 N | 088 29 13 W |
| Peterson Island | Island | 177 | Henry | 41 34 31 N | 090 10 50 W |
| Peterson Lake | Reservoir | 190 | Cook | 41 59 49 N | 087 52 05 W |
| Peterson Lake | Reservoir | 227 | Knox | 40 58 47 N | 090 09 08 W |
| Peterson Park | Park | 217 | Coles | 39 29 02 N | 088 21 23 W |
| Peterson Park | Park | 182 | Cook | 41 59 17 N | 087 43 14 W |
| Peterson Park | Park | 232 | McHenry | 42 21 37 N | 088 16 45 W |
| Peterson Park | Park | 199 | Rock Island | 41 30 33 N | 090 29 10 W |
| Peterson School | School | 224 | Winnebago | 42 14 39 N | 089 04 41 W |
| Peterson School (historical) | School | 268 | Lee | 41 49 59 N | 088 57 39 W |
| Peterson School (historical) | School | 224 | Vermilion | 40 22 42 N | 087 51 35 W |
| Peterson School (historical) | School | 221 | Will | 41 22 08 N | 087 45 58 W |
| Peterstown | Populated Place | 216 | La Salle | 41 29 53 N | 089 08 48 W |
| Petersville | Populated Place | 204 | Mercer | 41 16 46 N | 090 56 19 W |
| Peterville | Populated Place | 152 | Mason | 40 13 01 N | 089 59 35 W |
| Peterville Hall (historical) | Building | 152 | Mason | 40 13 56 N | 089 59 50 W |
| Peterville School (historical) | School | 152 | Mason | 40 13 36 N | 089 59 58 W |
| Petit Creek | Stream | | Hancock | 40 13 43 N | 091 25 08 W |
| Petite Lake | Lake | 223 | Lake | 42 25 53 N | 088 07 43 W |
| Petkiewitz Park | Park | 201 | Cook | 41 43 46 N | 087 49 59 W |
| Petrarca Park | Park | 210 | Cook | 41 29 44 N | 087 37 47 W |
| Petrea Cemetery | Cemetery | 140 | Clinton | 38 32 43 N | 089 14 54 W |
| Petri School (historical) | School | 156 | Brown | 39 56 20 N | 090 34 04 W |
| Petrolia | Populated Place | 137 | Lawrence | 38 45 38 N | 087 46 44 W |
| Pettibone Creek | Stream | | Lake | 42 18 30 N | 087 49 58 W |
| Pettifer Island | Island | 168 | Rock Island | 41 29 02 N | 090 36 39 W |
| Pettijohn Grave | Cemetery | 193 | Schuyler | 40 10 15 N | 090 50 27 W |
| Pettis Cemetery | Cemetery | 219 | Pike | 39 36 31 N | 090 42 46 W |
| Pettit Memorial Chapel | Church | 238 | Boone | 42 16 06 N | 088 50 59 W |
| Petty Branch | Stream | | Fayette | 39 11 46 N | 088 52 17 W |
| Petty Cemetery | Cemetery | 207 | Pike | 39 33 34 N | 090 48 35 W |
| Petty Cemetery | Cemetery | 166 | Pike | 39 31 54 N | 090 59 52 W |
| Petty Elementary School | School | 147 | Lawrence | 38 47 26 N | 087 51 00 W |
| Petty School (historical) | School | 140 | Lawrence | 38 47 29 N | 087 49 56 W |
| Petwyler School (historical) | School | 149 | Clay | 38 44 45 N | 088 31 37 W |
| Peugh Cemetery | Cemetery | 245 | Whiteside | 41 52 25 N | 089 48 30 W |
| Peyton Creek | Stream | | Peoria | 40 33 01 N | 089 50 29 W |
| Pfeiffer Hall | Building | 244 | McLean | 40 29 26 N | 088 59 37 W |
| Pfeiffer Memorial Hall | Building | 219 | DuPage | 41 46 29 N | 088 08 36 W |
| Pfeiffer School (historical) | School | 139 | Pike | 39 35 44 N | 091 08 56 W |
| Pfister Landing Strip | Airport | 218 | Woodford | 40 46 15 N | 088 59 00 W |
| Pflibsen School (historical) | School | 212 | La Salle | 41 10 41 N | 089 01 50 W |
| Pfundstein School (historical) | School | 219 | Will | 41 25 29 N | 087 55 19 W |
| Pharaoh Camp and Picnic Area | Locale | 258 | Saline | 37 36 07 N | 088 22 47 W |
| Pharoahs Gardens | Populated Place | 175 | Johnson | 37 35 34 N | 088 54 34 W |
| Pheasant Hill Plaza Shopping Center | Locale | 213 | Will | 41 41 39 N | 088 04 14 W |
| Pheasant Knolls (subdivision) | Populated Place | 244 | Lake | 42 13 22 N | 088 02 48 W |
| Pheasant Ridge Primary School | School | 244 | DuPage | 41 55 22 N | 088 05 21 W |
| Pheasant Run | Populated Place | 247 | Kane | 41 55 57 N | 088 22 05 W |
| Pheasant Run Access Area | Park | 180 | Christian | 39 37 45 N | 089 27 16 W |
| Pheasant Run Golf Course | Locale | 231 | DuPage | 41 55 05 N | 088 15 19 W |
| Pheasant Trails Park | Park | 203 | Cook | 41 31 56 N | 087 39 36 W |
| Phegley School (historical) | School | 154 | Randolph | 38 03 43 N | 089 59 47 W |
| Phelps | Populated Place | 128 | St. Clair | 38 29 21 N | 090 13 00 W |
| Phelps | Populated Place | 236 | Warren | 40 50 55 N | 090 34 29 W |
| Phelps School (historical) | School | 158 | Marion | 38 37 42 N | 088 53 32 W |
| Phelps School (historical) | School | 246 | Ogle | 42 03 03 N | 089 04 13 W |
| Phelps School (historical) | School | 190 | Peoria | 40 45 14 N | 089 58 03 W |
| Phelps School (historical) | School | 226 | Winnebago | 42 27 27 N | 089 08 54 W |
| Phelps Slough | Gut | 159 | Henderson | 40 54 09 N | 090 58 50 W |