- Population: 55,641 (Change since 1990: +13.8%)
- Created: December 19, 1821
- County seat: Farmington
- Largest town: Farmington (Pop. 13,924)
- Name origin: St. Francis River
- Ash Landing (Historical)
- Station on the St. Francois County Electric Line north of Farmington
- Big River Mills (Historical)
- Bismarck (Fourth-class city)
- Population: 1,470 (Change since 1990: -6.9%)
- Located on MO 32 between Caledonia and Park Hills
- Latitude & Longitude: 37°46'07" N, 90°37'31" W
- Name origin: Otto van Bismarck
- Founded: Nov. 10, 1868
- Blackwell (Unincorporated)
- Previously known as: Blackwells Station
- Located at end of Route CC in the far northern reach of the county.
- Latitude & Longitude: 38°02'37" N, 90°37'26" W
- Elevation: 588
- Civil township: Big River
- School district: Desoto 73
- USGS Quad: Vineland
- Station on the Iron Mountain Line
- Named for Jeremiah Blackwell, who settled
here with his family ca. 1818
- Sources: Goodspeed (See biographical sketch of Aquilla Blackwell and Jefferson County)
- Blairsville (Historical)
- Bonne Terre (Third-class city)
- Population: 4,039 (Change since 1990: +4.3%)
- Latitude & Longitude: 37°55'18" N, 90°33'06" W
- Name origin: "the good land"
- Founded: April 1864 by the St. Joseph Lead Company
- Clardy (Historical)
- Columbia Junction (Historical)
- Station on the St. Francois County Electric Line near Esther
- Cross Roads (Historical)
- Located at intersection of Old Jackson Road and Rock Creek Road southeast of Libertyville, near Route T
- Latitude & Longitude: 37°39'57" N, 90°14'48" W
- Survey: T. 34 N., R. 7 E., Sec. 10
- Elevation: 1011
- Civil township: Liberty
- USGS Quad: Womack (Not labeled, but shows Crossroads School)
- Cross Roads was at the intersection of the Farmington to Jackson Road
and the Fredericktown to Ste. Genevieve road.
- Maps: 1865 and 1872
- Davis (Unincorporated)
- Located on Davis Crossing Road between Leadwood and MO 32
- Latitude & Longitude: 37°49'18" N, 90°35'28" W
- Civil township: Randolph
- School district: West St. Francois County R-4
- USGS Quad: Flat River
- Daytown (Unincorporated)
- Appears to be within the city limits of Leadwood along MO 8
- Latitude & Longitude: 37°51'33" N, 90°34'53" W
- Civil township: Randolph
- School district: West St. Francois County R-4
- USGS Quad: Flat River
- De Lassus (Unincorporated)
- Alternate name: Delassus
- Located southwest of US 67 and Route W interchange near Farmington
- Latitude & Longitude: 37°45'52" N, 90°27'20" W
- Civil township: St. Francois
- School district: Farmington R-7
- USGS Quad: Farmington
- Station on Belmont Branch
- Founded: Oct. 1869 by A. D. De Lassus
- Maps: 1886, 1904 McNally (Shown as "Delassus"), and 1920 Clason (Shown as "DeLassus")
- Source: Goodspeed (p. 446)
- Dents Station (Historical)
- Previously known as: Dents Settlement
- Station on the Iron Mountain Line south of Bismarck
- Maps: 1861 Lloyd US (Dents) and 1872 (Shows Dents Station)
- Derby (Unincorporated)
- Alternate name: Derby Junction
- Located near the intersection of MO 32 and Route B just southwest
of Elvins (Park Hills)
- Latitude & Longitude: 37°49'30" N, 90°32'19" W
- Civil township: Randolph
- School district: Central R-3
- USGS Quad: Flat River
- Map: 1920 Clason
- Desloge (Fourth-class city)
- Population: 4,802 (Change since 1990: +15.7%)
- Latitude & Longitude: 37°52'22" N, 90°31'14" W
- Name origin: Firmin Desloge
- Founded: 1887 by Firmin Desloge
- Includes: Cantwell
- Doe Run (Unincorporated)
- Located at intersection Route W and Route B southwest of Farmington
- Latitude & Longitude: 37°44'34" N, 90°29'51" W
- Elevation: 940
- Civil township: Pendleton
- School district: Farmington R-7
- USGS Quad: Wachita Mountain
- Doe Run Junction (Historical)
- East Bonne Terre (Unincorporated)
- Located on Route K east of Bonne Terre
- Latitude & Longitude: 37°55'16" N, 90°31'39" W
- Civil township: Perry
- School district: North St. Francois County R-1
- USGS Quad: Bonne Terre
- Map: 1897 Galbraith
- Farmington (Third-class city)
- Population: 13,924 (Change since 1990: +20.1%)
- Located along US 67 between Park Hills and Fredericktown
- Latitude & Longitude: 37°46'55" N, 90°25'20" W
- Name origin: Agriculture
- Founded: 1822
- Post office: 1817-1823 (Murphy's Settlement), 1823-1825 (St. Francois Court House), 1825-Now (Farmington)
- Frankclay (Unincorporated)
- Previously known as: Claytown
- Located on Route M southwest of Leadwood
- Latitude & Longitude: 37°51'42" N, 90°36'54" W
- Civil township: Randolph
- School district: West St. Francois County R-4
- USGS Quad: Flat River
- Named for Franklin Eleazer Clay
- Fredonia (Historical)
- French Village (Unincorporated)
- Locatd on Route Y at intersection with Brickey Road, west of Route D
- Latitude & Longitude: 37°58'21" N, 90°23'23" W
- Elevation: 899
- Civil township: Marion
- School district: North St. Francois County R-1
- USGS Quad: French Village
- Post office: Jun. 29, 1857 - Now
- Map: 1857 Colton
- Goodfellow (Historical)
- Gumbo (Unincorporated)
- Located on MO 8 between Leadwood and Park Hills
- Latitude & Longitude: 37°51'45" N, 90°33'45" W
- Survey: T. 36 N., R. 4 E., Sec. 2
- Civil township: Randolph
- School district: North St. Francois County R-1
- USGS Quad: Flat River
- Halifax (Unincorporated)
- Located near the US 67 and Route Y intersection northeast of Bonne Terre
- Latitude & Longitude: 38°00'43" N, 90°29'23" W
- Survey: T. 38 N., R. 5 E., Sec. 16
- Civil township: Big River
- USGS Quad: Halifax
- Map: 1920 Clason
- Hamilton Town (Historical)
- Located just east of Doe Run
- Latitude & Longitude: 37°44'29" N, 90°29'01" W
- Survey: T. 35 N., R. 5 E., Sec. 16
- Elevation: 970
- Civil township: Pendleton
- USGS Quad: Wachita Mountain (Not shown)
- Hazel Run (Unincorporated)
- Alternate name: Hazel Run Mills
- Located at intersection Hillsboro Road and Hazel Run Road
between Bonne Terre and French Village
- Latitude & Longitude: 37°56'49" N, 90°27'56" W
- Elevation: 788
- Civil township: Marion
- School district: North St. Francois County R-1
- USGS Quad: French Village
- Maps: 1866, 1886, 1895 McNally, and 1920 Clason
- Highley Heights (Unincorporated)
- Located just north of Desloge at the interchange of US 67
and MO 8
- Latitude & Longitude: 37°52'53" N, 90°31'02" W
- Survey: T. 37 N., R. 5 E., Sec. 29
- Elevation: 761
- Civil township: Randolph
- School district: North St. Francois County R-1
- USGS Quad: Bonne Terre
- Hoffman Junction (Unincorporated)
- Located just south of Bonne Terre
- Latitude & Longitude: 37°54'36" N, 90°33'23" W
- Survey: T. 37 N., R. 4 E., Sec. 23
- Civil township: Perry
- School district: North St. Francois County R-1
- USGS Quad: Bonne Terre
- Junction of the Mississippi River and Bonne Terre Line and a spur
to Leadwood
- Hunt (Historical)
- Station on the St. Francois County Electric Line north of Farmington
- Hurryville (Unincorporated)
- Located on county road east of Leadington
- Latitude & Longitude: 37°50'24" N, 90°27'29" W
- Survey: T. 36 N., R. 5 E., Sec. 11
- Elevation: 851
- Civil township: St. Francois
- School district: Central R-3
- USGS Quad: Farmington
- Iron Mountain (Unincorporated)
- Located on Route W north of Middlebrook
- Latitude & Longitude: 37°41'43" N, 90°38'25" W
- Survey: T. 35 N., R. 4 E., Sec. 31
- Civil township: Iron
- School district: Bismarck R-5
- USGS Quad: Graniteville
- Named for Iron Mountain
- Post office: Jan. 20, 1846 - Jun. 18, 1976
- Iron Mountain Lake (Fourth-class city)
- Population: 693 (Change since 1990: +9.7%)
- Located off Route W south of Bismarck and east
of Iron Mountain
- Latitude & Longitude: 37°41'20" N, 90°37'23" W
- Name origin: Iron Mountain
- Founded: 1983
- Jaydee (Historical)
- Probably located near the Route K and Route D intersection south of French Village
- Latitude & Longitude: 37°55'34" N, 90°24'60" W
- Elevation: 790
- Civil township: Marion
- USGS Quad: French Village (Not shown)
- Name taken from the initials of J. D. Kennedy
- Maps: 1904 McNally and 1920 Clason
- Knauss (Historical)
- Station on the St. Francois County Electric Line north of Farmington
- Knob Lick (Unincorporated)
- Located near US 67 and Route DD intersection between
Fredericktown and Farmington
- Latitude & Longitude: 37°40'31" N, 90°22'02" W
- Elevation: 930
- Civil township: Liberty
- School district: Farmington R-7
- USGS Quad: Knob Lick
- Founded: 1865
- Koen (Historical)
- Station on the St. Francois County Electric Line near Hurryville, presumably along Koen Creek
- Koester (Unincorporated)
- Located on Koester Springs Road beyond the end of Route D northwest of French Village
- Latitude & Longitude: 38°01'20" N, 90°24'34" W
- Survey: T. 38 N., R. 6 E., Sec. 7
- Civil township: Marion
- School district: North St. Francois County R-1
- USGS Quad: Halifax
- Map: 1904 McNally
- Leadington (Fourth-class city)
- Population: 206 (Change since 1990: +2.5%)
- Located near US 67 and MO 32 interchange just outside
Park Hills
- Latitude & Longitude: 37°50'15" N, 90°29'10" W
- Name origin: lead
- Founded: 1902 by the Federal Land Company
- Leadwood (Fourth-class city)
- Population: 1,160 (Change since 1990: -7.0%)
- Located on MO 8 west of Park Hills
- Latitude & Longitude: 37°51'52" N, 90°35'26" W
- Name origin: lead
- Libertyville (Unincorporated)
- Previously known as: Kinkead, Locust Grove, and Liberty Meeting House
- Located at end of Route DD east of Knob Lick
- Latitude & Longitude: 37°42'13" N, 90°17'17" W
- Elevation: 912
- Civil township: Liberty
- School district: Farmington R-7
- USGS Quad: Knob Lick
- Founded: ca. 1810 by Capt. Samuel Kinkead
- Post office: 1846-1857 (Kinkead), 1857-1862 (Locust Grove),
1862-1863 (Liberty Meeting House), ca.1863-1919 (Libertyville)
- Maps: 1855 (Kinkead), 1857 Colton (Kinkead), 1866 (Locust Grove), and 1873 (Libertyville)
- Lopez (Unincorporated)
- Located between Middlebrook and Pilot Knob right on
the Iron County line
- Latitude & Longitude: 37°39'07" N, 90°38'47" W
- Survey: T. 34 N., R. 4 E., Sec. 18
- Civil township: Iron
- School district: Bismarck R-5
- USGS Quad: Graniteville
- Junction of the Iron Mountain mainline and the spur to Graniteville
- Loughboro (Unincorporated)
- Previously known as: Loughborough
- Located on Route B northwest of Doe Run
- Latitude & Longitude: 37°46'42" N, 90°31'19" W
- Civil township: St. Francois
- School district: Central R-3
- USGS Quad: Flat River
- Station on the Belmont Branch
- Map: 1920 Clason
- Mineral City (Unincorporated)
- Located on Route W southwest of Doe Run at the foot of Stono Mountain
- Latitude & Longitude: 37°42'59" N, 90°32'01" W
- Civil township: Pendleton
- School district: Farmington R-7
- USGS Quad: Iron Mountain Lake
- Mitchell (Unincorporated)
- Located on a county road southeast of Leadwood
- Latitude & Longitude: 37°50'48" N, 90°34'47" W
- Elevation: 903
- Civil township: Randolph
- School district: West St. Francois County R-4
- USGS Quad: Flat River
- Named for Quince Mitchell
- Ogborn (Unincorporated)
- Alternate name: Farmington Junction
- Located on Route D north of Farmington
- Latitude & Longitude: 37°49'52" N, 90°25'18" W
- Elevation: 954
- Civil township: St. Francois
- School district: Farmington R-7
- USGS Quad: Farmington
- Map: 1920 Clason
- Park Hills (Third-class city)
- Park Hills was created in 1994 from the consolidation
of Flat River, Elvins, Esther, and Rivermines.
- Population: 7,861 (2000 census)
- Latitude & Longitude: 37°50'40" N, 90°30'40" W
- Founded: January 1, 1994
- Includes: Elvins, Esther, Fairview Acres, Federal, Flat River, and Rivermines
- Rock Springs (Unincorporated)
- Located on Route W northeast of Doe Run
- Latitude & Longitude: 37°45'23" N, 90°28'60" W
- Civil township: Pendleton
- School district: Farmington R-7
- USGS Quad: Farmington
- Map: 1904 McNally
- Settletown (Historical)
- Located along Old Cadet Road northwest of Bonne Terre
- Latitude & Longitude: 37°57'02" N, 90°35'45" W
- Survey: T. 37 N., R. 4 E. Sec. 4
- Elevation: 807
- Civil township: Perry
- USGS Quad: Bonne Terre (Shows benchmark near Settle Cemetery)
- Named for original land owners William and Hattie Settle
- Silver Springs (Unincorporated)
- Located on old railroad line near US 67 northeast of Bonne Terre
- Latitude & Longitude: 37°59'57" N, 90°31'28" W
- Survey: T. 38 N., R. 5 E., Sec. 18
- Elevation: 808
- Civil township: Big River
- School district: North St. Francois County R-1
- USGS Quad: Bonne Terre
- Map: 1920 Clason
- St. Francois (Unincorporated)
- Appears to be within the city limits of Park Hills
- Latitude & Longitude: 37°51'23" N, 90°31'07" W
- Elevation: 805
- Civil township: St. Francois
- School district: Central R-3
- USGS Quad: Flat River (Not shown)
- Ste. Williams (Historical)
- Alternate name: St. Williams
- Located east
of Farmington near the Ste. Genevieve County line, probably near
Route F
- Station on the Saline Valley Line
- Map: 1920 Clason
- Stono (Historical)
- Syenite (Unincorporated)
- Located on Route DD just west of Knob Lick
- Latitude & Longitude: 37°40'36" N, 90°23'30" W
- Civil township: Liberty
- School district: Farmington R-7
- USGS Quad: Wachita Mountain
- Terre du Lac (Unincorporated)
- Large gated private subdivision covering 5,200 acres
- Located along the Washington County line west of Bonne Terre
and south of MO 47
- Latitude & Longitude: 37°54'42" N, 90°37'31" W
- Survey: T. 37 N., R. 4 E., Sec. 19
- Elevation: 980
- Civil township: Perry
- School district: West St. Francois County R-4
- USGS Quad: Mineral Point (Also shown on Bonne Terre quad)
- Tunnel (Historical)
- Located on old railroad grade near Silver Springs and Halifax
- Latitude & Longitude: 38°00'31" N, 90°30'46" W
- Elevation: 915
- Civil township: Big River
- USGS Quad: Vineland (Not shown)
- Map: 1920 Clason
- Turpin (Historical)
- Valley Forge (Historical)
- Located on MO 32 near Wolf Creek
- Latitude & Longitude: 37°47'07" N, 90°22'24" W
- Survey: T. 36 N., R. 6 E., Sec. 33
- Elevation: 856
- Civil township: St. Francois
- USGS Quad: Sprott (Benchmark shown)
- Map: 1877
- Whitener (Historical)
- Station on the St. Francois County Electric Line near Farmington
- Wolf Creek (Historical)
- Located along the old railroad grade near the confluence of
St. Francis River and Wolf Creek southeast of Delassus
- Latitude & Longitude: 37°43'49" N, 90°24'22" W
- Survey: T. 35 N., R. 6 E., Sec. 19
- Elevation: 834
- Civil township: St. Francois
- USGS Quad: Wachita Mountain (Benchmark shown)
- Station on Belmont Branch four miles northwest of Knob Lick
- Woodland Park (Historical)
- Alternate name: Woodland
- Station on the St. Francois County Electric Line near Hurryville
- Wortham (Unincorporated)
- Located on county road southeast of Frankclay
and west of Mitchell
- Latitude & Longitude: 37°50'40" N, 90°36'31" W
- Civil township: Randolph
- School district: West St. Francois County R-4
- USGS Quad: Flat River
Name origin
Named after the St. Francis River
| Year | Population | Percent change |
|---|
| 1830 | 2,366 | -- |
| 1840 | 3,211 | +35.7% |
| 1850 | 4,964 | +54.6% |
| 1860 | 7,249 | +46.0% |
| 1870 | 9,742 | +34.4% |
| 1880 | 13,822 | +41.9% |
| 1890 | 17,347 | +25.5% |
| 1900 | 24,051 | +38.6% |
| 1910 | 35,738 | +48.6% |
| 1920 | 31,403 | -12.1% |
| 1930 | 35,832 | +14.1% |
| 1940 | 35,950 | +0.3% |
| 1950 | 35,276 | -1.9% |
| 1960 | 36,516 | +3.5% |
| 1970 | 36,875 | +1.0% |
| 1980 | 42,600 | +15.5% |
| 1990 | 48,904 | +14.8% |
| 2000 | 55,641 | +13.8% |