Information compiled from the sources shown.
From History of Clarion County, published circa 1976, compiler unknown.
| Year | Population | Year | Population | |
|---|---|---|---|---|
| 1835 | 11,000 estimated? |
1840 | 15,587 | |
| 1850 | 23,565 | 1860 | 24,988 | |
| 1870 | 26,537 | 1880 | 40,328 | |
| 1890 | 36,540 | 1900 | 24,283 | |
| 1910 | 36,638 | 1920 | 36,170 | |
| 1930 | 34,516 | 1940 | 38,410 | |
| 1950 | 38,344 | 1960 | 37,408 | |
| 1970 | 38,414 | 1980 | 43,362 | |
| 1990 | 41,699 | 2000 | 41,765 |
- Click here for statistical/demographic breakdown for the year 2000.
From Caldwell's Illustrated Historical Combination Atlas of Clarion Co., Pennsylvania, published by J. A. Caldwell, 1877.
In 1840, the townships comprising Clarion County and the population of each, although reported in the census returns of the county to which they had formerly belonged, were as follows:
| Townships from Armstrong County | |
|---|---|
| Clarion | 2,239 |
| Madison | 1,305 |
| Monroe | 1,151 |
| Perry | 1,122 |
| Redbank | 3,070 |
| Toby | 1,829 |
| Townships from Venango County | |
|---|---|
| Beaver | 1,611 |
| Elk | 585 |
| Farmington | 799 |
| Paint | 491 |
| Richland | 1,388 |
| Total population: 15,587 | |
The population of the county in 1850 was 23,565; in 1860, 24,988; and in 1870, 26,537. [Note that these figures do not match those in the table below, which is taken from the same source.]
Within the past six years, large numbers have been attracted to the county by the oil business, and from the last election returns it is safe to estimate the present population at or near 40,000. The marked increase from 1840 to 1850 was owing to the rapid development of the iron and lumber interests, especially the former.
Population of Townships and Boroughs for 1850, 1860, and 1876
| 1876 | 1860 | 1850 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Location | Total | Native | Foreign | White | Colored | Colored | White | Colored | White | |||
| Ashland Township | 758 | 696 | 62 | 758 | ... | 732 | ||||||
| Beaver Township | 1338 | 1274 | 64 | 1338 | ... | 1315 | ... | 2791 | 13 | |||
| Brady Township | 263 | 244 | 19 | 263 | ||||||||
| Clarion Township | 1059 | 1036 | 23 | 1059 | ... | 949 | 6 | 1769 | 29 | |||
| Elk Township | 1055 | 945 | 110 | 1055 | ... | 956 | 7 | 1479 | 5 | |||
| Farmington Township | 1642 | 1499 | 143 | 1642 | ... | 1442 | 7 | 1117 | 7 | |||
| Highland Township | 524 | 512 | 12 | 524 | ||||||||
| Knox Township | 656 | 505 | 151 | 656 | ... | 549 | ||||||
| Licking Township | 1218 | 1184 | 34 | 1218 | ... | 1388 | ||||||
| Limestone Township | 1375 | 1343 | 32 | 1375 | ... | 1352 | ... | 1452 | 10 | |||
| Madison Township | 1935 | 1795 | 140 | 1935 | ... | 2120 | 10 | 1360 | 5 | |||
| Mill Creek Township | 517 | 496 | 21 | 517 | ... | 393 | ||||||
| Monroe Township | 1334 | 1308 | 26 | 1332 | 2 | 1321 | 10 | 1287 | 8 | |||
| Paint Township | 346 | 305 | 41 | 334 | 12 | 343 | ... | 610 | ||||
| Perry Township | 1568 | 1525 | 43 | 1568 | ... | 1540 | ... | 1394 | ||||
| Piney Township | 1160 | 1083 | 77 | 1160 | ... | 1365 | 1 | 910 | ||||
| Porter Township | 1546 | 1520 | 26 | 1546 | ... | 1695 | ... | 1606 | 1 | |||
| Redbank Township | 1434 | 1388 | 46 | 1434 | ... | 1286 | ... | 1225 | ||||
| Richland Township | 1015 | 963 | 52 | 1014 | 1 | 960 | 1 | 1360 | ||||
| Salem Township | 749 | 925 | 24 | 949 | ... | 848 | ||||||
| Toby Township | 1140 | 1122 | 18 | 1140 | ... | 1100 | ... | 2233 | 1 | |||
| Washington Township | 1240 | 1045 | 195 | 1240 | ... | 1191 | ... | 1226 | 1 | |||
| Callensburg Borough | 255 | 251 | 4 | 255 | ... | 319 | ||||||
| Clarion Borough | 709 | 648 | 61 | 699 | 10 | 627 | 21 | 682 | 37 | |||
| Curllsville Borough | 208 | 201 | 7 | 208 | ||||||||
| East Brady Borough | 728 | 552 | 176 | 727 | 1 | |||||||
| Edenburg Borough | ||||||||||||
| New Bethlehem Borough | 348 | 342 | 6 | 348 | ... | 380 | ||||||
| Rimersburg Borough | 324 | 313 | 11 | 324 | ... | 346 | ||||||
| St. Petersburg Borough | ||||||||||||
| Strattonville Borough | 356 | 349 | 7 | 356 | ... | 323 | ||||||
| Totals | 27024 | 25367 | 1631 | 26974 | 26 | 24840 | 63 | 22500 | 117 | |||
Notes
(a) St. Petersburg and Edenburg boroughs were counted with Richland and Beaver Townships in 1870. They became boroughs since that date. Supposed population now (1877) is estimated at about two thousand each.
(b) Also one Indian. [Note: no indication of which census this corresponds to.]
Supposed census of Clarion County now (1877) about 40,000.
