Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Union Baptist Church | Church | 174 | Vermilion | 40 07 59 N | 087 37 25 W |
| Union Brick School | School | 192 | Montgomery | 39 15 40 N | 089 28 54 W |
| Union Cemetery | Cemetery | 176 | Bond | 39 01 22 N | 089 31 35 W |
| Union Cemetery | Cemetery | 272 | Bureau | 41 33 22 N | 089 27 33 W |
| Union Cemetery | Cemetery | 256 | Bureau | 41 34 47 N | 089 16 47 W |
| Union Cemetery | Cemetery | 232 | Carroll | 42 00 07 N | 089 45 12 W |
| Union Cemetery | Cemetery | 199 | Coles | 39 38 28 N | 088 06 29 W |
| Union Cemetery | Cemetery | 247 | Cook | 42 07 29 N | 088 13 11 W |
| Union Cemetery | Cemetery | 191 | Cumberland | 39 22 22 N | 088 04 50 W |
| Union Cemetery | Cemetery | 216 | De Witt | 40 14 16 N | 089 07 45 W |
| Union Cemetery | Cemetery | 147 | Edwards | 38 23 49 N | 088 01 14 W |
| Union Cemetery | Cemetery | 189 | Effingham | 39 04 13 N | 088 45 02 W |
| Union Cemetery | Cemetery | 188 | Effingham | 39 04 13 N | 088 44 56 W |
| Union Cemetery | Cemetery | 198 | Fayette | 39 02 43 N | 089 05 52 W |
| Union Cemetery | Cemetery | 290 | Kane | 42 02 15 N | 088 32 57 W |
| Union Cemetery | Cemetery | 239 | Kane | 41 55 41 N | 088 18 32 W |
| Union Cemetery | Cemetery | 234 | Knox | 40 58 01 N | 090 16 23 W |
| Union Cemetery | Cemetery | 205 | La Salle | 41 11 59 N | 088 58 53 W |
| Union Cemetery | Cemetery | 289 | Lee | 41 41 48 N | 089 08 56 W |
| Union Cemetery | Cemetery | 288 | Lee | 41 50 57 N | 088 56 33 W |
| Union Cemetery | Cemetery | 213 | Livingston | 40 58 44 N | 088 22 41 W |
| Union Cemetery | Cemetery | 219 | Livingston | 41 00 40 N | 088 31 49 W |
| Union Cemetery | Cemetery | 183 | Logan | 40 08 13 N | 089 23 03 W |
| Union Cemetery | Cemetery | 203 | Macon | 39 55 13 N | 088 50 56 W |
| Union Cemetery | Cemetery | 202 | Macoupin | 39 26 34 N | 089 59 44 W |
| Union Cemetery | Cemetery | 146 | Marion | 38 31 07 N | 088 45 07 W |
| Union Cemetery | Cemetery | 259 | McHenry | 42 13 50 N | 088 33 02 W |
| Union Cemetery | Cemetery | 283 | McHenry | 42 14 36 N | 088 19 39 W |
| Union Cemetery | Cemetery | 205 | Morgan | 39 40 10 N | 090 07 01 W |
| Union Cemetery | Cemetery | 189 | Peoria | 40 37 23 N | 089 49 35 W |
| Union Cemetery | Cemetery | 102 | Pulaski | 37 15 09 N | 089 14 42 W |
| Union Cemetery | Cemetery | 167 | Randolph | 38 05 17 N | 089 43 18 W |
| Union Cemetery | Cemetery | 197 | Sangamon | 39 40 58 N | 089 55 12 W |
| Union Cemetery | Cemetery | 212 | Shelby | 39 32 08 N | 088 51 53 W |
| Union Cemetery | Cemetery | 191 | Shelby | 39 17 43 N | 088 42 39 W |
| Union Cemetery | Cemetery | 138 | St. Clair | 38 33 11 N | 089 46 25 W |
| Union Cemetery | Cemetery | 302 | Stephenson | 42 28 08 N | 089 31 46 W |
| Union Cemetery | Cemetery | 244 | Tazewell | 40 44 25 N | 089 25 42 W |
| Union Cemetery | Cemetery | 186 | Union | 37 23 24 N | 089 12 26 W |
| Union Cemetery | Cemetery | 136 | White | 38 12 59 N | 088 04 17 W |
| Union Cemetery | Cemetery | 149 | White | 37 59 30 N | 088 18 52 W |
| Union Cemetery | Cemetery | 237 | Will | 41 25 36 N | 087 48 25 W |
| Union Center | Populated Place | 186 | Cumberland | 39 19 58 N | 088 04 53 W |
| Union Center School (historical) | School | 223 | Champaign | 40 17 48 N | 088 12 49 W |
| Union Center School (historical) | School | 193 | Fulton | 40 19 10 N | 090 23 30 W |
| Union Central School (historical) | School | 207 | Douglas | 39 39 09 N | 088 18 09 W |
| Union Chapel | Church | 177 | Fulton | 40 16 19 N | 090 20 42 W |
| Union Chapel | Church | 185 | Jefferson | 38 25 56 N | 088 50 52 W |
| Union Chapel | Church | 207 | Macon | 39 50 04 N | 089 03 05 W |
| Union Chapel | Church | 199 | Macoupin | 39 26 57 N | 089 51 43 W |
| Union Chapel | Church | 205 | Moultrie | 39 46 09 N | 088 30 42 W |
| Union Chapel | Church | 120 | Saline | 37 48 16 N | 088 36 18 W |
| Union Chapel Cemetery | Cemetery | 182 | Fulton | 40 16 22 N | 090 20 42 W |
| Union Chapel Cemetery | Cemetery | 198 | Fulton | 40 20 09 N | 090 23 34 W |
| Union Chapel Cemetery | Cemetery | 118 | Gallatin | 37 50 47 N | 088 20 48 W |
| Union Chapel Cemetery | Cemetery | 183 | Jefferson | 38 25 56 N | 088 50 48 W |
| Union Chapel Cemetery | Cemetery | 200 | Macoupin | 39 26 57 N | 089 51 44 W |
| Union Chapel United Methodist Church | Church | 175 | Lawrence | 38 43 52 N | 087 49 00 W |
| Union Church | Church | 178 | Crawford | 38 54 40 N | 087 42 47 W |
| Union Church | Church | 159 | Effingham | 38 56 14 N | 088 35 19 W |
| Union Church | Church | 160 | Franklin | 37 52 59 N | 088 47 24 W |
| Union Church | Church | 153 | Hamilton | 38 06 40 N | 088 40 28 W |
| Union Church | Church | 152 | Hardin | 37 28 10 N | 088 24 03 W |
| Union Church | Church | 204 | Iroquois | 40 33 56 N | 087 53 40 W |
| Union Church | Church | 167 | Jackson | 37 40 31 N | 089 15 30 W |
| Union Church | Church | 159 | Jefferson | 38 20 28 N | 089 08 42 W |
| Union Church | Church | 206 | Kankakee | 41 03 10 N | 087 37 30 W |
| Union Church | Church | 220 | Lee | 41 38 59 N | 089 26 57 W |
| Union Church | Church | 202 | Macon | 39 55 13 N | 088 50 54 W |
| Union Church | Church | 158 | Mason | 40 23 26 N | 089 43 00 W |
| Union Church | Church | 199 | Mercer | 41 16 39 N | 090 59 49 W |
| Union Church | Church | 216 | Peoria | 40 50 25 N | 089 53 06 W |
| Union Church | Church | 136 | Wayne | 38 20 45 N | 088 15 35 W |
| Union Church | Church | 164 | White | 37 59 44 N | 088 18 59 W |
| Union Church | Church | 139 | White | 38 12 59 N | 088 04 20 W |
| Union Church (historical) | Church | 228 | Carroll | 42 00 09 N | 089 45 10 W |
| Union Church (historical) | Church | 158 | Greene | 39 26 20 N | 090 14 56 W |
| Union Church (historical) | Church | 242 | Jo Daviess | 42 21 51 N | 090 07 58 W |
| Union Church (historical) | Church | 192 | McDonough | 40 20 21 N | 090 44 01 W |
| Union Church (historical) | Church | 204 | McDonough | 40 24 41 N | 090 34 46 W |
| Union Church (historical) | Church | 188 | Shelby | 39 17 43 N | 088 42 34 W |
| Union Church (historical) | Church | 244 | Tazewell | 40 44 24 N | 089 25 38 W |
| Union Church (historical) | Church | 154 | Union | 37 29 51 N | 089 03 24 W |
| Union Church (historical) | Church | 287 | Winnebago | 42 23 24 N | 089 22 09 W |
| Union Church of Hinsdale | Church | 218 | DuPage | 41 48 01 N | 087 55 36 W |
| Union Community Center | Locale | 128 | Perry | 37 57 15 N | 089 29 04 W |
| Union Congregational Church | Church | 145 | Edwards | 38 23 50 N | 088 01 13 W |
| Union Congregational Church | Church | 215 | Rock Island | 41 29 47 N | 090 27 56 W |
| Union Corner Cemetery | Cemetery | 209 | Kankakee | 41 13 08 N | 087 39 46 W |
| Union Corner United Methodist Church | Church | 201 | Vermilion | 40 04 25 N | 087 33 13 W |
| Union County | Civil | 203 | Union | 37 27 00 N | 089 15 02 W |
| Union County Country Club | Locale | 160 | Union | 37 26 06 N | 089 14 48 W |
| Union County Courthouse | Building | 173 | Union | 37 27 05 N | 089 16 06 W |
| Union County Hospital | Hospital | 190 | Union | 37 27 53 N | 089 14 48 W |
| Union County State Conservation Area | Park | 104 | Union | 37 24 30 N | 089 22 32 W |
| Union County State Forest | Forest | 186 | Union | 37 29 41 N | 089 20 39 W |
| Union Depot | Building | 235 | Warren | 40 54 21 N | 090 39 19 W |
| Union District Number 1 Election Precinct | Civil | 104 | Union | 37 24 10 N | 089 24 01 W |
| Union District Number 2 Election Precinct | Civil | 108 | Union | 37 31 20 N | 089 26 29 W |
| Union Ditch | Canal | 208 | Will | 41 31 42 N | 087 49 12 W |
| Union Ditch Number 1 | Canal | 259 | DeKalb | 41 54 38 N | 088 39 07 W |
| Union Ditch Number 2 | Canal | 259 | DeKalb | 41 54 32 N | 088 36 24 W |
| Union Ditch Number 3 | Canal | 257 | Kane | 41 55 58 N | 088 35 36 W |
| Union Douglas Elementary School | School | 202 | Hancock | 40 24 37 N | 091 08 07 W |
| Union Drainage District Number 3 | Canal | 204 | Coles | 39 32 56 N | 088 13 59 W |
| Union Drainage Ditch | Canal | 117 | Wayne | 38 22 37 N | 088 10 16 W |
| Union Drainage Ditch | Canal | 194 | Whiteside | 41 45 28 N | 089 42 20 W |
| Union Drainage Ditch Number 1 | Canal | 207 | Champaign | 40 11 46 N | 088 05 25 W |
| Union Elementary School | School | 194 | Will | 41 29 50 N | 088 01 27 W |
| Union Forest Church | Church | 157 | Jersey | 39 04 45 N | 090 25 51 W |