- Population: 61,296 (Change since 1990: +6.2%)
- Created: February 28, 1839
- County seat: Marion
- Largest town: Marion (Pop. 16,035)
- Name origin: Williamson County, Tennessee
- Attila (Unincorporated)
- Located northeast of Crab Orchard
- Latitude & Longitude: 37°46'11" N, 88°46'16" W
- Survey: T. 9 S., R. 4 E.
- Elevation: 562
- Civil township: Crab Orchard
- USGS Quad: Pittsburg
- Map: 1878
- Bainbridge (Unincorporated)
- Latitude & Longitude: 37°44'02" N, 88°59'35" W
- Elevation: 432
- Civil township: West Marion
- USGS Quad: Marion
- Maps: 1856 Colton and 1875 Asher
- Bakers Crossroads (Unincorporated)
- Latitude & Longitude: 37°37'41" N, 89°06'53" W
- Elevation: 598
- Civil township: Grassy
- USGS Quad: Crab Orchard Lake (Not shown)
- Banklick (Unincorporated)
- Located southwest of Galatia on the
Saline County line
- Latitude & Longitude: 37°49'38" N, 88°42'08" W
- Elevation: 424
- USGS Quad: Harco
- Blairsville (Unincorporated)
- Located between Cambria and Hurst
- Latitude & Longitude: 37°48'40" N, 89°07'25" W
- Survey: T. 8 S., R. 1 E., Sec. 20
- Elevation: 399
- Civil township: Blairsville
- USGS Quad: Herrin
- Bush (Village)
- Population: 257 (Change since 1990: -26.8%)
- Located just northeast of Hurst along IL 149
- Latitude & Longitude: 37°50'36" N, 89°07'52" W
- Cambria (Village)
- Population: 1,330 (Change since 1990: +8.1%)
- Located northwest of Carterville
- Latitude & Longitude: 37°46'53" N, 89°07'09" W
- Carterville (City)
- Population: 4,616 (Change since 1990: +27.2%)
- Located between Carbondale and Marion
- Latitude & Longitude: 37°45'36" N, 89°04'38" W
- Post office: May 27, 1837 - Now
- Chamness (Unincorporated)
- Located southwest of Marion
- Latitude & Longitude: 37°40'37" N, 88°59'19" W
- Survey: T. 10 S., R. 2 E.
- Elevation: 457
- Civil township: Southern
- USGS Quad: Marion
- Chittyville (Unincorporated)
- Located on IL 148 just north of Herrin
- Latitude & Longitude: 37°49'46" N, 89°01'40" W
- Survey: T. 8 S., R. 2 E., Sec. 18
- Elevation: 395
- Civil township: Herrin
- USGS Quad: Herrin
- Clifford (Unincorporated)
- Located just north of Colp and northwest of Herrin
- Latitude & Longitude: 37°49'25" N, 89°04'38" W
- Survey: T. 8 S., R. 1 E., Sec. 14
- Elevation: 388
- Civil township: Blairsville
- USGS Quad: Herrin
- Clifty Heights (Unincorporated)
- Latitude & Longitude: 37°36'02" N, 88°56'37" W
- Elevation: 540
- Civil township: Southern
- USGS Quad: Goreville
- Colp (Village)
- Population: 224 (Change since 1990: -4.7%)
- Located west of Herrin
- Latitude & Longitude: 37°48'19" N, 89°04'48" W
- Name origin: John Colp
- Founded: by John Colp
- Corinth (Unincorporated)
- Located east of Johnston City
- Latitude & Longitude: 37°49'08" N, 88°46'35" W
- Survey: T. 8 S., R. 4 E.
- Elevation: 519
- Civil township: Corinth
- USGS Quad: Pittsburg
- Crab Orchard (Unincorporated)
- Located on IL 13 between Marion and Harrisburg
- Latitude & Longitude: 37°43'45" N, 88°48'15" W
- Survey: T. 9 S., R. 4 E.
- Elevation: 495
- Civil township: Crab Orchard
- USGS Quad: Crab Orchard
- Crab Orchard Estates (Unincorporated)
- Located just north of IL 13 near Crab Orchard Lake
- Latitude & Longitude: 37°44'58" N, 89°08'51" W
- Survey: T. 9 S., R. 1 E., Sec. 7
- Elevation: 419
- Civil township: Carterville
- USGS Quad: Carbondale
- Crainville (Village)
- Population: 992 (Change since 1990: -2.6%)
- Located just southeast of Carterville
- Latitude & Longitude: 37°45'07" N, 89°04'04" W
- Creal Springs (City)
- Population: 702 (Change since 1990: -11.3%)
- Located on IL 166 between Marion and New Burnside
- Latitude & Longitude: 37°37'10" N, 88°50'12" W
- Name origin: Edward G. Creal
- Post office: Sep. 22, 1846 - Now
- Crenshaw Crossing (Unincorporated)
- Alternate name: Crenshaw
- Latitude & Longitude: 37°46'26" N, 88°58'46" W
- Elevation: 440
- Civil township: West Marion
- USGS Quad: Johnston City
- Crestwood (Unincorporated)
- Latitude & Longitude: 37°36'16" N, 88°56'24" W
- Elevation: 540
- Civil township: Southern
- USGS Quad: Goreville
- Dewmaine (Unincorporated)
- Located between Colp and Carterville
- Latitude & Longitude: 37°46'50" N, 89°04'37" W
- Survey: T. 8 S., R. 1 E., Sec. 34
- Elevation: 434
- Civil township: Blairsville
- USGS Quad: Herrin
- Post office: Mar. 6, 1901 - July 31, 1931
- Dog Walk (Unincorporated)
- Alternate name: Cedar Grove
- Latitude & Longitude: 37°45'33" N, 88°55'58" W
- Elevation: 504
- Civil township: West Marion
- USGS Quad: Johnston City
- Eden Park (Unincorporated)
- Located along IL 148 just south of Energy
- Latitude & Longitude: 37°45'18" N, 89°01'26" W
- Survey: T. 9 S., R. 2 E., Sec. 7
- Elevation: 455
- Civil township: West Marion
- USGS Quad: Herrin
- Energy (Village)
- Population: 1,175 (Change since 1990: +6.2%)
- Located just south of Herrin along IL 148
- Latitude & Longitude: 37°46'26" N, 89°01'35" W
- Fergestown (Unincorporated)
- Located east of Herrin
- Latitude & Longitude: 37°47'33" N, 88°57'53" W
- Survey: T. 8 S., R. 2 E.
- Elevation: 451
- Civil township: Herrin
- USGS Quad: Johnston City
- Fopal (Unincorporated)
- Latitude & Longitude: 37°36'23" N, 88°56'25" W
- Elevation: 530
- Civil township: Southern
- USGS Quad: Goreville
- Fredonia (Unincorporated)
- Latitude & Longitude: 37°46'04" N, 89°07'08" W
- Elevation: 425
- Civil township: Carterville
- USGS Quad: Herrin (Not shown)
- Map: 1875 Asher
- Freeman Spur (Village)
- Population: 273 (Change since 1990: -5.9%)
- Located between Herrin and West Frankfort near
the Franklin County line
- Latitude & Longitude: 37°51'40" N, 88°59'50" W
- Hartford (Unincorporated)
- Latitude & Longitude: 37°48'17" N, 88°39'56" W
- Elevation: 439
- USGS Quad: Harco
- Herrin (City)
- Population: 11,298 (Change since 1990: +4.1%)
- Located northwest of Marion, west of Johnston City,
and northeast of Carterville along IL 148
- Latitude & Longitude: 37°48'11" N, 89°01'39" W
- Herrin Junction (Unincorporated)
- Located just northeast of Herrin
- Latitude & Longitude: 37°49'27" N, 89°00'40" W
- Survey: T. 8 S., R. 2 E., Sec. 17
- Elevation: 395
- Civil township: Herrin
- USGS Quad: Herrin
- Hudgens (Unincorporated)
- Located on IL 37 south of Marion
- Latitude & Longitude: 37°39'18" N, 88°56'27" W
- Survey: T. 10 S., R. 2 E.
- Elevation: 495
- Civil township: Southern
- USGS Quad: Marion
- Named for Alex Hudgens, postmaster
- Hurst (City)
- Population: 805 (Change since 1990: -4.4%)
- Located along IL 149 northwest of Herrin near
the Jackson and Franklin County lines and next to Bush
- Latitude & Longitude: 37°49'59" N, 89°08'34" W
- Jenkins (Unincorporated)
- Latitude & Longitude: 37°51'15" N, 88°55'39" W
- Elevation: 450
- Civil township: Lake Creek
- USGS Quad: Johnston City
- Johnston City (City)
- Population: 3,557 (Change since 1990: -4.0%)
- Located north of Marion
- Latitude & Longitude: 37°49'14" N, 88°55'39" W
- Post office: Dec. 10, 1852 - Now
- Kelleys (Unincorporated)
- Latitude & Longitude: 37°36'11" N, 88°57'38" W
- Elevation: 585
- Civil township: Southern
- USGS Quad: Goreville
- Lake Crest (Unincorporated)
- Latitude & Longitude: 37°36'22" N, 88°55'03" W
- Elevation: 520
- Civil township: Creal Springs
- USGS Quad: Goreville
- Marion (City)
- Population: 16,035 (Change since 1990: +10.2%)
- Located near the interchange
of I-57 and IL 13 between Carbondale and Harrisburg
- Latitude & Longitude: 37°43'50" N, 88°55'59" W
- Post office: Jan. 30, 1840 - Now
- Neilson (Unincorporated)
- Located along IL 37 between Marion and Goreville
- Latitude & Longitude: 37°37'49" N, 88°57'38" W
- Survey: T. 10 S., R. 2 E.
- Elevation: 515
- Civil township: Southern
- USGS Quad: Marion
- New Dennison (Unincorporated)
- Located on IL 166 southeast of Marion
- Latitude & Longitude: 37°41'34" N, 88°51'20" W
- Survey: T. 9 S., R. 3 E.
- Elevation: 450
- Civil township: East Marion
- USGS Quad: Crab Orchard
- Oak Hill (Historical)
- Located somewhere northeast of Marion
- Latitude & Longitude: 37°47'26" N, 88°49'18" W
- Civil township: Lake Creek
- USGS Quad: Pittsburg
- Map: 1878
- Paineville (Unincorporated)
- Located just east of Herrin
- Latitude & Longitude: 37°48'32" N, 89°00'06" W
- Survey: T. 8 S., R. 2 E., Sec. 20-21
- Elevation: 400
- Civil township: Herrin
- USGS Quad: Herrin
- Palzo (Unincorporated)
- Located northeast of Creal Springs
- Latitude & Longitude: 37°38'55" N, 88°45'48" W
- Survey: T. 10 S., R. 4 E.
- Elevation: 440
- Civil township: Stonefort
- USGS Quad: Crab Orchard
- Paulton (Unincorporated)
- Located north of Crab Orchard
- Latitude & Longitude: 37°45'50" N, 88°48'14" W
- Survey: T. 9 S., R. 4 E.
- Elevation: 538
- Civil township: Crab Orchard
- USGS Quad: Pittsburg
- Pittsburg (Village)
- Population: 575 (Change since 1990: -4.5%)
- Located northeast of Marion
- Latitude & Longitude: 37°46'37" N, 88°50'58" W
- Name origin: Pittsburgh, Pennsylvania
- Post office: Mar. 10, 1907 - Now
- Pulleys Mill (Unincorporated)
- Located on IL 37 near the Johnson County line
- Latitude & Longitude: 37°36'00" N, 88°58'46" W
- Elevation: 600
- Civil township: Southern
- USGS Quad: Goreville
- Rileyville (Unincorporated)
- Latitude & Longitude: 37°51'02" N, 88°40'22" W
- Elevation: 400
- USGS Quad: Harco
- Rodgersville (Unincorporated)
- Latitude & Longitude: 37°40'36" N, 88°46'11" W
- Elevation: 450
- Civil township: Stonefort
- USGS Quad: Crab Orchard
- Shakerag (Unincorporated)
- Latitude & Longitude: 37°49'20" N, 88°54'32" W
- Elevation: 422
- Civil township: Lake Creek
- USGS Quad: Johnston City
- Sleepy Hollow (Unincorporated)
- Latitude & Longitude: 37°36'01" N, 88°56'57" W
- Elevation: 535
- Civil township: Southern
- USGS Quad: Goreville
- Spillertown (Village)
- Population: 220 (Change since 1990: -11.6%)
- Located just north of Marion
- Latitude & Longitude: 37°45'59" N, 88°55'10" W
- Stiritz (Unincorporated)
- Located just northwest of Johnston City
- Latitude & Longitude: 37°50'10" N, 88°56'54" W
- Survey: T. 8 S., R. 2 E.
- Elevation: 400
- Civil township: Herrin
- USGS Quad: Johnston City
- Sulphur Springs (Unincorporated)
- Latitude & Longitude: 37°36'17" N, 88°50'29" W
- Elevation: 514
- Civil township: Creal Springs
- USGS Quad: Creal Springs
- Sunset Harbor (Unincorporated)
- Latitude & Longitude: 37°36'60" N, 88°56'05" W
- Elevation: 520
- Civil township: Southern
- USGS Quad: Goreville
- Timmons (Unincorporated)
- Latitude & Longitude: 37°42'42" N, 88°57'54" W
- Elevation: 430
- Civil township: West Marion
- USGS Quad: Marion
- White Ash (Village)
- Population: 268 (Change since 1990: +7.6%)
- Located between Johnston City and Marion
- Latitude & Longitude: 37°47'22" N, 88°55'29" W
- Willeford (Unincorporated)
- Previously known as: Canaville
- Located along IL 166 south of New Dennison
- Latitude & Longitude: 37°39'22" N, 88°51'06" W
- Survey: T. 10 S., R. 3 E., Sec. 11
- Elevation: 492
- Civil township: Creal Springs
- USGS Quad: Crab Orchard
- Named for William H. Willeford, postmaster
- Post office: May 31, 1888 - Feb. 12, 1905 (Canaville), Feb. 12, 1905 - Sept. 30, 1912 (Willeford)
- Wolf Creek (Unincorporated)
- Located southwest of Marion
- Latitude & Longitude: 37°37'36" N, 89°03'10" W
- Survey: T. 10 S., R. 1 E., Sec. 25
- Elevation: 600
- Civil township: Grassy
- USGS Quad: Crab Orchard Lake
- Map: 1878
- Woodland Hills (Unincorporated)
- Latitude & Longitude: 37°36'27" N, 88°56'40" W
- Elevation: 530
- Civil township: Southern
- USGS Quad: Goreville
Name origin
Named for Williamson County, Tennessee
| Year | Population | Percent change |
|---|
| 1840 | 4,457 | -- |
| 1850 | 7,216 | +61.9% |
| 1860 | 12,196 | +69.0% |
| 1870 | 17,329 | +42.1% |
| 1880 | 19,324 | +11.5% |
| 1890 | 22,226 | +15.0% |
| 1900 | 27,796 | +25.1% |
| 1910 | 45,098 | +62.2% |
| 1920 | 61,092 | +35.5% |
| 1930 | 53,880 | -11.8% |
| 1940 | 51,424 | -4.6% |
| 1950 | 48,621 | -5.5% |
| 1960 | 46,117 | -5.2% |
| 1970 | 49,021 | +6.3% |
| 1980 | 56,538 | +15.3% |
| 1990 | 57,733 | +2.1% |
| 2000 | 61,296 | +6.2% |