- Population: 4,800 (Change since 1990: -7.5%)
- Created: March 2, 1839
- County seat: Elizabethtown
- Largest town: Rosiclare (Pop. 1,213)
- Name origin: Hardin County, Kentucky
- Cadiz (Unincorporated)
- Located east of Karbers Ridge
- Latitude & Longitude: 37°34'45" N, 88°13'35" W
- Survey: T. 11 S., R. 9 E., Sec. 9
- Elevation: 565
- Precinct: Rock
- USGS Quad: Saline Mines
- Cave-in-Rock (Village)
- Population: 346 (Change since 1990: -9.2%)
- Located along the Ohio River at the south end of IL 1
- Latitude & Longitude: 37°28'09" N, 88°09'55" W
- Eichorn (Unincorporated)
- Located on IL 34 north of Shetlerville
- Latitude & Longitude: 37°29'28" N, 88°24'19" W
- Survey: T. 12 S., R. 7 E., Sec. 11
- Elevation: 440
- Precinct: Stone Church
- USGS Quad: Shetlerville
- Elizabethtown (Village)
- Population: 348 (Change since 1990: -18.5%)
- Located on IL 146 just upstream from Rosiclare on the Ohio River
- Latitude & Longitude: 37°26'45" N, 88°18'18" W
- Post office: May 8, 1840 - Now
- Fairview (Unincorporated)
- Latitude & Longitude: 37°24'57" N, 88°21'24" W
- Elevation: 389
- Precinct: West Rosiclare
- USGS Quad: Rosiclare
- Finneyville (Unincorporated)
- Latitude & Longitude: 37°32'40" N, 88°06'19" W
- Elevation: 550
- Precinct: Rock
- USGS Quad: Dekoven
- Gross (Unincorporated)
- Located southeast of Karbers Ridge
- Latitude & Longitude: 37°31'59" N, 88°17'26" W
- Survey: T. 11 S., R. 8 E., Sec. 26
- Elevation: 620
- Precinct: Monroe
- USGS Quad: Karbers Ridge
- Hicks (Unincorporated)
- Located southwest of Karbers Ridge
- Latitude & Longitude: 37°32'35" N, 88°22'32" W
- Survey: T. 11 S., R. 8 E., Sec. 24
- Elevation: 570
- Precinct: Monroe
- USGS Quad: Herod
- Humm Wye (Unincorporated)
- Located the junction of IL 34 and IL 146 south of Eichorn
- Latitude & Longitude: 37°27'38" N, 88°24'22" W
- Survey: T. 12 S., R. 7 E., Sec. 23
- Elevation: 451
- Precinct: Stone Church
- USGS Quad: Shetlerville
- Karbers Ridge (Unincorporated)
- Located on Karbers Ridge Road
- Latitude & Longitude: 37°34'47" N, 88°19'60" W
- Survey: T. 11 S., R. 8 E., Sec. 9
- Elevation: 604
- Precinct: Monroe
- USGS Quad: Karbers Ridge
- Lamb (Unincorporated)
- Located northeast of Cave in Rock
- Latitude & Longitude: 37°31'54" N, 88°07'29" W
- Survey: T. 11 S., R. 10 E.
- Elevation: 390
- Precinct: Rock
- USGS Quad: Dekoven
- Loves Corner (Unincorporated)
- Latitude & Longitude: 37°29'44" N, 88°10'14" W
- Elevation: 449
- Precinct: Cave-In-Rock
- USGS Quad: Cave-in-Rock
- Mineral City (Unincorporated)
- Latitude & Longitude: 37°24'34" N, 88°21'12" W
- Elevation: 340
- Precinct: West Rosiclare
- USGS Quad: Rosiclare
- Peters Creek (Unincorporated)
- Latitude & Longitude: 37°29'16" N, 88°14'29" W
- Elevation: 453
- Precinct: McFarlan
- USGS Quad: Cave-in-Rock
- Rock Creek (Unincorporated)
- Latitude & Longitude: 37°32'12" N, 88°13'38" W
- Survey: T. 11 S., R. 9 E., Sec. 29
- Elevation: 562
- Precinct: Rock
- USGS Quad: Saline Mines
- Rosiclare (City)
- Population: 1,213 (Change since 1990: -12.0%)
- Located southwest of Elizabethtown on the Ohio River
- Latitude & Longitude: 37°25'25" N, 88°20'46" W
- Saline Landing (Unincorporated)
- Located at the end of Tucker Hill Road near the mouth
of Saline River
- Latitude & Longitude: 37°34'12" N, 88°07'49" W
- Survey: T. 11 S., R. 10 E., Sec. 8
- Elevation: 370
- Precinct: Rock
- USGS Quad: Saline Mines
- Shetlerville (Unincorporated)
- Located west of Elizabethtown
- Latitude & Longitude: 37°25'50" N, 88°24'27" W
- Survey: T. 12 S., R. 7 E., Sec. 35
- Elevation: 457
- Precinct: Stone Church
- USGS Quad: Shetlerville
- Sparks Hill (Unincorporated)
- Located east of Karbers Ridge
- Latitude & Longitude: 37°35'05" N, 88°17'13" W
- Survey: T. 11 S., R. 8 E., Sec. 11
- Elevation: 600
- Precinct: Monroe
- USGS Quad: Karbers Ridge
- Stone (Unincorporated)
- Wolrab Mill (Unincorporated)
- Alternate name: Wolrab Mills
- Latitude & Longitude: 37°30'31" N, 88°20'24" W
- Precinct: Stone Church
- USGS Quad: Karbers Ridge
- Post office: Sept. 9, 1872 - Sept. 30, 1904 (Wolrab Mills)
- Map: 1883 Tenney
Name origin
Named for Hardin County, Kentucky
| Year | Population | Percent change |
|---|
| 1840 | 1,378 | -- |
| 1850 | 2,887 | +109.5% |
| 1860 | 3,750 | +29.9% |
| 1870 | 5,113 | +36.3% |
| 1880 | 6,024 | +17.8% |
| 1890 | 7,234 | +20.1% |
| 1900 | 7,448 | +3.0% |
| 1910 | 7,015 | -5.8% |
| 1920 | 7,533 | +7.4% |
| 1930 | 6,955 | -7.7% |
| 1940 | 7,759 | +11.6% |
| 1950 | 7,530 | -3.0% |
| 1960 | 5,879 | -21.9% |
| 1970 | 4,914 | -16.4% |
| 1980 | 5,383 | +9.5% |
| 1990 | 5,189 | -3.6% |
| 2000 | 4,800 | -7.5% |