- Population: 17,609 (Change since 1990: -2.8%)
- Created: March 24, 1873
- County seats: Corning and Piggott
- Largest town: Piggott (Pop. 3,894)
- Name origin: Henry Clay
- Bell City (Unincorporated)
- Located southwest of Nimmons on CR 530
- Latitude & Longitude: 36°17'16" N, 90°07'19" W
- Survey: T. 19 N., R. 9 E., Sec. 16
- Elevation: 265
- Civil township: Payne
- USGS Quad: Kennett North
- Boydsville (Unincorporated)
- Located at eastern intersection AR 90 and AR 141
- Latitude & Longitude: 36°20'03" N, 90°23'01" W
- Survey: T. 20 N., R. 6 E., Sec. 25
- Elevation: 340
- Civil township: Johnson
- USGS Quad: Boydsville
- Founded: 1877
- Map: 1878
- Brookings (Unincorporated)
- Located west of Peach Orchard on Spur AR 280
- Latitude & Longitude: 36°17'06" N, 90°43'14" W
- Survey: T. 19 N., R. 3 E., Sec. 14
- Elevation: 270
- Civil township: Clark
- USGS Quad: Peach Orchard
- Cache Lake (Unincorporated)
- Located on AR 135 southeast of Knobel
- Latitude & Longitude: 36°17'44" N, 90°31'59" W
- Survey: T. 19 N., R. 5 E., Sec. 10
- Elevation: 288
- Civil township: Wilson
- USGS Quad: Knobel
- Carryville (Unincorporated)
- Located on CR 528 north of Nimmons
- Latitude & Longitude: 36°20'32" N, 90°06'14" W
- Survey: T. 20 N., R. 9 E., Sec. 27
- Elevation: 275
- Civil township: Swain
- USGS Quad: Kennett North
- Map: 1914
- Corning (City)
- Population: 3,679 (Change since 1990: +10.7%)
- Located at intersection US 62 and US 67
- Latitude & Longitude: 36°24'28" N, 90°34'47" W
- Crockett (Unincorporated)
- Located at intersection CR 431 and CR 450 west of Piggott
- Latitude & Longitude: 36°22'33" N, 90°19'50" W
- Survey: T. 20 N., R. 7 E., Sec. 9
- Elevation: 350
- Civil township: Bradshaw
- USGS Quad: Pollard
- Datto (Town)
- Population: 97 (Change since 1990: -19.2%)
- Located along US 67 near the Randolph County line
- Latitude & Longitude: 36°23'30" N, 90°43'51" W
- Greenway (Town)
- Population: 244 (Change since 1990: +15.1%)
- Located on US 49 southwest of Piggott
- Latitude & Longitude: 36°20'28" N, 90°13'13" W
- Hammett (Historical)
- Located on the railroad between Rector and Greenway
- Latitude & Longitude: 36°18'51" N, 90°14'30" W
- Elevation: 275
- Civil township: Haywood
- USGS Quad: Greenway
- Map: 1898 McNally (Hammetts)
- Hargrave Corner (Unincorporated)
- Located at junction US 49 and AR 90 east of Rector
- Latitude & Longitude: 36°15'33" N, 90°13'45" W
- Elevation: 255
- Civil township: Blue Cane
- USGS Quad: Greenway
- Heelstring (Unincorporated)
- Located on CR 116 southwest of Corning
- Latitude & Longitude: 36°21'13" N, 90°41'40" W
- Elevation: 286
- Civil township: Kilgore
- USGS Quad: Peach Orchard
- Heubner (Unincorporated)
- Located on a county road southwest of Rector
- Latitude & Longitude: 36°13'01" N, 90°18'43" W
- Survey: T. 18 N., R. 7 E., Sec. 3
- Elevation: 256
- Civil township: Oak Bluff
- USGS Quad: Mounds
- Hickoria (Unincorporated)
- Located on CR 247 (old railroad grade) southwest of McDougal
- Latitude & Longitude: 36°23'28" N, 90°26'36" W
- Elevation: 290
- Civil township: Lemmons
- USGS Quad: McDougal
- Holly Island (Unincorporated)
- Located at eastern intersection AR 90 and AR 139 east of Rector
- Latitude & Longitude: 36°15'33" N, 90°09'29" W
- Elevation: 265
- Civil township: Blue Cane
- USGS Quad: Greenway
- Knob (Unincorporated)
- Located on AR 141 southwest of Boydsville
- Latitude & Longitude: 36°16'53" N, 90°26'53" W
- Survey: T. 19 N., R. 6 E., Sec. 17
- Elevation: 347
- Civil township: Knob
- USGS Quad: Boydsville
- Knobel (Town)
- Population: 358 (Change since 1990: +12.9%)
- Located on AR 90 south of Corning
- Latitude & Longitude: 36°19'12" N, 90°36'07" W
- Leonard (Unincorporated)
- Located on AR 139 southeast of Rector
- Latitude & Longitude: 36°13'11" N, 90°14'58" W
- Survey: T. 18 N., R. 8 E., Sec. 5
- Elevation: 260
- Civil township: Blue Cane
- USGS Quad: Senath
- Lower Boydsville (Unincorporated)
- Located just west of Boydsville on AR 90
- Latitude & Longitude: 36°20'02" N, 90°24'30" W
- Survey: T. 20 N., R. 6 E., Sec. 26
- Elevation: 302
- Civil township: Johnson
- USGS Quad: Boydsville
- Luehrmann (Unincorporated)
- Located along the railroad between Corning and Knobel just south
of Black River, near the end of CR 228
- Latitude & Longitude: 36°21'45" N, 90°35'20" W
- Survey: T. 20 N., R. 4 E., Sec. 24
- Elevation: 290
- Civil township: Cache
- USGS Quad: Knobel (Not shown)
- McDougal (Town)
- Population: 195 (Change since 1990: -6.2%)
- Located at intersection US 62 and AR 141
- Latitude & Longitude: 36°26'24" N, 90°23'29" W
- Mitchell (Unincorporated)
- Located just west of Greenway on CR 481
- Latitude & Longitude: 36°20'13" N, 90°14'04" W
- Elevation: 305
- Civil township: Haywood
- USGS Quad: Greenway
- Moark (Unincorporated)
- Located on CR 154 just east of US 67 near the Missouri border
- Latitude & Longitude: 36°28'60" N, 90°31'30" W
- Survey: T. 21 N., R. 5 E., Sec. 3
- Elevation: 299
- Civil township: Cleveland
- USGS Quad: Corning
- Nimmons (Town)
- Population: 100 (Change since 1990: +4.2%)
- Located near junction CR 534 and CR 528 northeast of Holly Island and northwest of Kennett, MO
- Latitude & Longitude: 36°18'24" N, 90°05'40" W
- Palatka (Unincorporated)
- Located on a county road north of AR 328, northeast of Success
- Latitude & Longitude: 36°27'59" N, 90°39'28" W
- Survey: T. 21 N., R. 4 E., Sec. 16
- Elevation: 296
- Civil township: Brown
- USGS Quad: Datto
- Patterson (Unincorporated)
- Located northeast of Holly Island
- Latitude & Longitude: 36°16'20" N, 90°07'18" W
- Survey: T. 19 N., R. 9 E., Sec. 21
- Elevation: 267
- Civil township: Payne
- USGS Quad: Kennett North
- Map: 1914
- Peach Orchard (Town)
- Population: 195 (Change since 1990: -1.0%)
- Located at junction AR 90 and AR 280 southwest of Knobel
- Latitude & Longitude: 36°16'43" N, 90°39'46" W
- Piggott (City)
- Population: 3,894 (Change since 1990: +3.1%)
- Located at junction US 49 and US 62
- Latitude & Longitude: 36°22'58" N, 90°11'26" W
- Pollard (Town)
- Population: 240 (Change since 1990: +4.8%)
- Located at junction US 62 and AR 139 northwest of Piggott
- Latitude & Longitude: 36°25'51" N, 90°16'06" W
- Pratt (Unincorporated)
- Located on CR 481 just northeast of Rector
- Latitude & Longitude: 36°17'18" N, 90°15'57" W
- Elevation: 283
- Civil township: Oak Bluff
- USGS Quad: Rector
- Rector (City)
- Population: 2,017 (Change since 1990: -11.1%)
- Located near intersections US 49, AR 90, and AR 119
- Latitude & Longitude: 36°15'47" N, 90°17'33" W
- Rhyne (Unincorporated)
- Located on CR 547 southeast of Piggott
- Latitude & Longitude: 36°21'29" N, 90°08'22" W
- Elevation: 277
- Civil township: Swain
- USGS Quad: Greenway
- Sellmeyer (Historical)
- Located along the abandoned railroad southeast of Knobel
- Latitude & Longitude: 36°17'25" N, 90°35'13" W
- Survey: T. 19 N., R. 5 E., Sec. 18
- Elevation: 280
- Civil township: Cache
- USGS Quad: Knobel (Benchmark shown)
- St. Francis (City)
- Population: 250 (Change since 1990: +24.4%)
- Located along US 62 on the west bank of St. Francis River
- Latitude & Longitude: 36°27'12" N, 90°08'43" W
- Styra (Unincorporated)
- Located northwest of Pollard
- Latitude & Longitude: 36°27'30" N, 90°18'19" W
- Elevation: 305
- Civil township: Pollard
- USGS Quad: Pollard (Not shown)
- Success (Town)
- Population: 180 (Change since 1990: +5.9%)
- Located at junction AR 211 and AR 328 northwest of Corning
- Latitude & Longitude: 36°27'16" N, 90°43'17" W
- Tipperary (Unincorporated)
- Located along AR 90 between intersections with AR 135 and AR 141 west of Boydsville
- Latitude & Longitude: 36°20'03" N, 90°28'21" W
- Elevation: 287
- Civil township: Johnson
- USGS Quad: Boydsville
- Trammellville (Unincorporated)
- Trinnon (Unincorporated)
- Located just east of Piggott on US 62 near junction with AR 1
- Latitude & Longitude: 36°22'58" N, 90°08'58" W
- Survey: T. 20 N., R. 9 E., Sec. 7
- Elevation: 278
- Civil township: St. Francis
- USGS Quad: Piggott
- Twin Oaks (Unincorporated)
- Latitude & Longitude: 36°24'43" N, 90°40'04" W
- Elevation: 294
- Civil township: Kilgore
- USGS Quad: Datto
- Walnut Grove (Unincorporated)
- Located along AR 135 near the intersection with CR 250 southeast of Corning
- Latitude & Longitude: 36°22'17" N, 90°31'29" W
- Survey: T. 20 N., R. 5 E., Sec. 15
- Elevation: 290
- Civil township: Gleghorn
- USGS Quad: Knobel (Shows benchmark and Walnut Grove Church)
- West Kennett (Unincorporated)
- Located south of Patterson and northwest of Kennett, MO
- Latitude & Longitude: 36°15'35" N, 90°07'18" W
- Survey: T. 19 N., R. 9 E., Sec. 20
- Elevation: 262
- Civil township: Payne
- USGS Quad: Kennett North
Name origin
First named for James M. Clayton, but on Dec. 6, 1875 the county
name was shortened to Clay in honor of Henry Clay
| Year | Population | Percent change |
|---|
| 1880 | 7,213 | -- |
| 1890 | 12,200 | +69.1% |
| 1900 | 15,886 | +30.2% |
| 1910 | 23,690 | +49.1% |
| 1920 | 27,276 | +15.1% |
| 1930 | 27,278 | +0.0% |
| 1940 | 28,386 | +4.1% |
| 1950 | 26,674 | -6.0% |
| 1960 | 21,258 | -20.3% |
| 1970 | 18,771 | -11.7% |
| 1980 | 20,616 | +9.8% |
| 1990 | 18,107 | -12.2% |
| 2000 | 17,609 | -2.8% |