- Population: 10,344 (Change since 1990: +9.2%)
- Created: February 14, 1854
- County seat: Alton
- Largest town: Thayer (Pop. 2,201)
- Name origin: Territory of Oregon
- Alton (Fourth-class city)
- Population: 668 (Change since 1990: -3.5%)
- Located near intersection US 160 and MO 19 in the center
of the county
- Latitude & Longitude: 36°41'39" N, 91°23'57" W
- Name origin: Alton, Illinois
- Founded: 1859
- American (Historical)
- Railroad station located northwest of Thayer
- Latitude & Longitude: 36°34'35" N, 91°35'15" W
- Survey: T. 22 N., R. 6 W., Sec. 11
- Elevation: 800
- Civil township: Big Apple
- School district: Oregon-Howell R-3
- USGS Quad: Thayer (Not shown)
- Attie (Historical)
- Located north of Koshkonong
- Survey: T. 24 N., R. 6 W., Sec. 8
- Bandyville (Historical)
- Located somewhere northwest of Greer
- Latitude & Longitude: 36°50'30" N, 91°24'27" W
- Survey: T. 25 N., R. 4 W., Sec. 17
- Civil township: Woodside
- School district: Alton R-4
- USGS Quad: Piedmont Hollow (Not shown)
- Named for J. R. Bandy, storeowner and doctor
- Map: 1904 McNally
- Source: Moser
- Billmore (Unincorporated)
- Located along MO 142 just east of the intersection with Route Y
- Latitude & Longitude: 36°33'46" N, 91°12'54" W
- Survey: T. 22 N., R. 2 W., Sec. 17-18
- Elevation: 585
- Civil township: Billmore
- School district: Couch R-1
- USGS Quad: Billmore
- Named for William Moore, early settler
- Source: Moser
- Boze Mill (Unincorporated)
- Located along the Eleven Point River north of Riverton
on CR 152
- Latitude & Longitude: 36°39'47" N, 91°11'38" W
- Elevation: 453
- Civil township: Ozark
- School district: Alton R-4
- USGS Quad: Riverton
- Brady (Historical)
- Probably located near the intersection of US 160 and Route M near Rover
- Latitude & Longitude: 36°44'37" N, 91°31'10" W
- Survey: T. 24 N., R. 6 W., Sec. 15
- Elevation: 982
- Civil township: Moore
- USGS Quad: Rover
- Named for L. Brady Harris, local lawyer
- Source: Moser
- Braswell (Historical)
- Located at intersection Route AA and CR 125 northwest of Many Springs
- Latitude & Longitude: 36°42'50" N, 91°18'39" W
- Survey: T. 24 N., R. 3 W., Sec. 29
- Elevation: 974
- Civil township: Goebel
- School district: Alton R-4
- USGS Quad: Many Springs (Shows Braswell Lookout Tower)
- Named for the Braswell family which settled here in 1856
- Source: Moser
- Calm (Unincorporated)
- Located at junction MO 142 and Route UU east of Billmore
- Latitude & Longitude: 36°33'06" N, 91°09'42" W
- Survey: T. 22 N., R. 2 W., Sec. 14
- Elevation: 502
- Civil township: Cedar Bluff
- School district: Couch R-1
- USGS Quad: Billmore
- Clifton (Unincorporated)
- Latitude & Longitude: 36°33'24" N, 91°31'48" W
- Survey: T. 22 N., R. 5 W.
- Elevation: 645
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Thayer
- Coin (Unincorporated)
- Located somewhere northeast of Many Springs
- Latitude & Longitude: 36°41'22" N, 91°14'13" W
- Survey: T. 24 N., R. 3 W., Sec. 36
- Elevation: 690
- Civil township: Goebel
- School district: Alton R-4
- USGS Quad: Riverton
- Named for Coin Jones, who settled here with his father about 1894
- Map: 1904 McNally
- Source: Moser
- Corona (Unincorporated)
- Located somewhere northwest of Jeff
- Latitude & Longitude: 36°33'04" N, 91°24'42" W
- Survey: T. 22 N., R. 4 W., Sec. 21
- Civil township: Jeff
- School district: Thayer R-2
- USGS Quad: Couch
- Map: 1904 McNally
- Couch (Unincorporated)
- Located along Route A west of the intersection with Route E,
south of Alton
- Latitude & Longitude: 36°36'22" N, 91°22'59" W
- Survey: T. 23 N., R. 4 W., Sec. 34
- Civil township: Couch
- School district: Couch R-1
- USGS Quad: Couch
- Post office: Apr. 10, 1885 - Now
- Deckard-Y (Unincorporated)
- Alternate name: Jenkins Store
- Located at the intersection of MO 142 and Route H
- Latitude & Longitude: 36°32'46" N, 91°15'14" W
- Survey: T. 22 N., R. 3 W., Sec. 23
- Elevation: 640
- Civil township: Myrtle
- School district: Couch R-1
- USGS Quad: Myrtle
- Map: MoDOT (Jenkins Store)
- Del Haf (Historical)
- Post office in the early 1920's
- Alternate name: Del Haff
- Name coined from founder Jasper L. Morris' daughter
Della and the halfway location of the place between Myrtle
and Jeff
- Source: Moser
- Farewell (Unincorporated)
- Located along Route V near the Arkansas Border between Thayer and Myrtle
- Latitude & Longitude: 36°30'04" N, 91°21'41" W
- Survey: T. 21 N., R. 4 W., Sec. 2
- Elevation: 779
- Civil township: Jeff
- School district: Couch R-1
- USGS Quad: Myrtle
- Garfield (Unincorporated)
- Located just off Route E southeast of Couch
- Latitude & Longitude: 36°35'07" N, 91°19'33" W
- Survey: T. 22 N., R. 3 W., Sec. 7
- Civil township: Couch
- School district: Couch R-1
- USGS Quad: Myrtle
- Green Town (Unincorporated)
- Located on the southern edge of Thayer
- Latitude & Longitude: 36°30'51" N, 91°32'32" W
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Thayer
- Greer (Unincorporated)
- Located on MO 19 northeast of Alton
- Latitude & Longitude: 36°46'10" N, 91°21'12" W
- Survey: T. 24 N., R. 4 W., Sec. 1
- Elevation: 853
- Civil township: Woodside
- School district: Alton R-4
- USGS Quad: Greer
- Griswold (Unincorporated)
- Located in the southeastern corner of the county beyond the end of Route UU
- Latitude & Longitude: 36°30'41" N, 91°08'41" W
- Survey: T. 22 N., R. 2 W., Sec. 35
- Elevation: 484
- Civil township: Cedar Bluff
- School district: Couch R-1
- USGS Quad: Billmore (Benchmark shown)
- Guiteau (Historical)
- Latitude & Longitude: 36°32'49" N, 91°18'47" W
- Survey: T. 22 N., R. 3 W., Sec. 20
- Elevation: 728
- Civil township: Jeff
- School district: Couch R-1
- USGS Quad: Myrtle (Not shown)
- Named for Charles J. Guiteau, who assassinated President
James Garfield in 1881.
- Source: Moser
- Hollis (Unincorporated)
- Located just southeast of Braswell
- Latitude & Longitude: 36°42'16" N, 91°18'18" W
- Survey: T. 24 N., R. 3 W., Sec. 28
- Elevation: 888
- Civil township: Goebel
- School district: Alton R-4
- USGS Quad: Many Springs (Shows Hollis Cemetery)
- Huddleston (Historical)
- Located on US 160 northwest of Alton
- Latitude & Longitude: 36°43'39" N, 91°25'29" W
- Survey: T. 24 N., R. 4 W., Sec. 20
- Elevation: 941
- Civil township: Piney
- School district: Alton R-4
- USGS Quad: Alton (Shows benchmark and Huddleston Chapel nearby)
- Hy (Unincorporated)
- Located southwest of Couch
- Latitude & Longitude: 36°34'31" N, 91°27'28" W
- Survey: T. 22 N., R. 5 W., Sec. 12
- Elevation: 715
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Couch
- Map: 1904 McNally
- Jeff (Unincorporated)
- Located on Route V just west of Farewell
- Latitude & Longitude: 36°30'27" N, 91°23'17" W
- Survey: T. 21 N., R. 4 W., Sec. 3
- Civil township: Jeff
- School district: Couch R-1
- USGS Quad: Couch
- Jobe (Unincorporated)
- Located at intersection CR 225 and CR 223 beyond the end of Route KK
- Latitude & Longitude: 36°35'06" N, 91°16'13" W
- Survey: T. 22 N., R. 3 W., Sec. 2
- Elevation: 458
- Civil township: Jobe
- School district: Couch R-1
- USGS Quad: Myrtle
- Koshkonong (Fourth-class city)
- Population: 205 (Change since 1990: +3.5%)
- Located along US 63 northwest of Thayer
- Latitude & Longitude: 36°35'45" N, 91°38'44" W
- Name origin: Lake Koshkonong, Wisconsin
- Founded: 1882
- Lula (Unincorporated)
- Alternate name: Lulu
- Located near intersection CR 104 and CR 125 east of Alton
- Latitude & Longitude: 36°41'19" N, 91°18'18" W
- Elevation: 774
- Civil township: Goebel
- School district: Alton R-4
- USGS Quad: Many Springs (Shows Lula Church)
- Named for Lula Stairs, wife of postmaster William J. Stairs
- Map: 1920 Clason
- Source: Moser
- Many Springs (Unincorporated)
- Located on US 160 near the junction with Route FF southeast of Alton
- Latitude & Longitude: 36°39'12" N, 91°15'59" W
- Survey: T. 23 N., R. 3 W., Sec. 14
- Civil township: Johnson
- School district: Alton R-4
- USGS Quad: Many Springs
- Midway (Unincorporated)
- Latitude & Longitude: 36°36'38" N, 91°28'37" W
- Survey: T. 23 N., R. 5 W.
- Elevation: 892
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Couch
- Mitch (Historical)
- Myrtle (Unincorporated)
- Located on Route V near the intersection with Route BB
- Latitude & Longitude: 36°30'31" N, 91°16'01" W
- Survey: T. 22 N., R. 3 W., Sec. 35
- Elevation: 566
- Civil township: Myrtle
- School district: Couch R-1
- USGS Quad: Myrtle
- Named for Myrtle Moore, daughter of founder Scott More
- New Liberty (Unincorporated)
- Previously known as: Brawley
- Located at intersection FR 3170 and FR 3150 northwest of Wilderness
- Latitude & Longitude: 36°51'52" N, 91°16'50" W
- Survey: T. 25 N., R. 3 W., Sec. 3
- Civil township: Falling Spring
- School district: Winona R-3
- USGS Quad: Greer
- Map: 1920 Clason (Brawley or New Liberty PO)
- Old Town (Unincorporated)
- Located between Thayer and Mammoth Spring, Arkansas
- Latitude & Longitude: 36°30'14" N, 91°32'36" W
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Thayer
- Map: MoDOT
- Riverton (Unincorporated)
- Located at the US 160 bridge over the Eleven Point River
- Latitude & Longitude: 36°38'54" N, 91°12'05" W
- Survey: T. 23 N., R. 2 W., Sec. 17
- Elevation: 441
- Civil township: Johnson
- School district: Alton R-4
- USGS Quad: Riverton
- Named for Riverton, Wyoming
- Source: Moser
- Ross (Unincorporated)
- Latitude & Longitude: 36°48'58" N, 91°17'12" W
- Survey: T. 25 N., R. 3 W., Sec. 21
- Elevation: 768
- Civil township: Falling Spring
- School district: Alton R-4
- USGS Quad: Greer (Benchmark shown)
- Rover (Unincorporated)
- Located at junction Route M and Route DD between West Plains and Alton
- Latitude & Longitude: 36°43'18" N, 91°37'15" W
- Survey: T. 24 N., R. 6 W., Sec. 21-22
- Elevation: 966
- Civil township: Highland
- School district: Alton R-4
- USGS Quad: Rover
- Royal Oak (Unincorporated)
- Located on US 160 northwest of Alton
- Latitude & Longitude: 36°44'02" N, 91°28'20" W
- Survey: T. 24 N., R. 5 W., Sec. 24
- Elevation: 908
- Civil township: Moore
- School district: Alton R-4
- USGS Quad: Alton
- Shelby (Unincorporated)
- Located southeast of Thayer, near the Arkansas border
- Latitude & Longitude: 36°30'13" N, 91°31'20" W
- Civil township: Thayer
- School district: Thayer R-2
- USGS Quad: Thayer
- Simpson (Unincorporated)
- Located southeast of Alton near intersection of Route E and CR 206
- Latitude & Longitude: 36°39'38" N, 91°22'25" W
- Survey: T. 23 N., R. 4 W., Sec. 11
- Elevation: 762
- Civil township: Piney
- School district: Alton R-4
- USGS Quad: Many Springs (Not shown)
- St. Elmo (Historical)
- Located along the railroad between Koshkonong and Thayer
- Latitude & Longitude: 36°35'03" N, 91°38'03" W
- Survey: T. 22 N., R. 6 W., Sec. 9
- Elevation: 965
- Civil township: Big Apple
- USGS Quad: Koshkonong (Shows a "St. Elmore" benchmark)
- Maps: 1904 McNally, 1920 Clason, and 1928 Frisco
- Thayer (Fourth-class city)
- Population: 2,201 (Change since 1990: +10.3%)
- Located near intersections US 63, MO 19, and MO 142 north
of Mammoth Spring, Arkansas
- Latitude & Longitude: 36°31'28" N, 91°32'17" W
- Name origin: Nathaniel Thayer
- Thomasons Mill (Historical)
- Latitude & Longitude: 36°33'44" N, 91°10'60" W
- Survey: T. 22 N., R. 2 W., Sec. 16
- Elevation: 400
- Civil township: Billmore
- School district: Couch R-1
- USGS Quad: Billmore (Not shown)
- Thomasville (Unincorporated)
- Located at the MO 99 bridge over the Eleven Point River northwest
of Alton
- Latitude & Longitude: 36°47'21" N, 91°31'55" W
- Survey: T. 25 N., R. 5 W., Sec. 32
- Elevation: 643
- Civil township: Moore
- School district: Alton R-4
- USGS Quad: Thomasville
- Founded: 1846
- Source: Moser
- Turners Mill (Unincorporated)
- Located on the Eleven Point River a few miles downstream from the MO 19 bridge
- Latitude & Longitude: 36°45'59" N, 91°15'59" W
- Survey: T. 24 N., R. 3 W., Sec. 3
- Civil township: King
- School district: Alton R-4
- USGS Quad: Greer
- Wason (Unincorporated)
- Water (Unincorporated)
- Located northeast of Calm along Route U
- Latitude & Longitude: 36°35'39" N, 91°08'49" W
- Survey: T. 22 N., R. 2 W., Sec. 2
- Elevation: 619
- Civil township: Cedar Bluff
- School district: Couch R-1
- USGS Quad: Billmore (Benchmark shown)
- Map: 1904 McNally
- Wilderness (Unincorporated)
- Located at end of Route K in the northeast corner of the county
- Latitude & Longitude: 36°47'20" N, 91°11'31" W
- Survey: T. 25 N., R. 2 W., Sec. 32
- Elevation: 843
- Civil township: King
- School district: Alton R-4
- USGS Quad: Wilderness
- Woodside (Unincorporated)
- Latitude & Longitude: 36°44'30" N, 91°23'17" W
- Survey: T. 24 N., R. 4 W., Sec. 15
- Elevation: 880
- Civil township: Woodside
- School district: Alton R-4
- USGS Quad: Alton
- Named for John R. Woodside, early settler
- Source: Moser
Name origin
Named for the "Territory of Oregon"
| Year | Population | Percent change |
|---|
| 1850 | 1,432 | -- |
| 1860 | 3,009 | +110.1% |
| 1870 | 3,287 | +9.2% |
| 1880 | 5,791 | +76.2% |
| 1890 | 10,467 | +80.7% |
| 1900 | 13,906 | +32.9% |
| 1910 | 14,081 | +1.3% |
| 1920 | 12,889 | -8.5% |
| 1930 | 12,220 | -5.2% |
| 1940 | 13,390 | +9.6% |
| 1950 | 11,978 | -10.5% |
| 1960 | 9,845 | -17.8% |
| 1970 | 9,180 | -6.8% |
| 1980 | 10,238 | +11.5% |
| 1990 | 9,470 | -7.5% |
| 2000 | 10,344 | +9.2% |