Piatt County, Illinois
Piatt County: county in Illinois, United States
About
Piatt County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 16,729 and a population density of 15 people per km². After 10 years in 2020 county had an estimated population of 16,355 inhabitants. Its county seat is Monticello. The county was created 185 years ago in 1840.
County Snapshot
Piatt County at a glance
Piatt County currently has 8 quality-checked populated place pages linked on MapSof, making it easier to jump from the county overview into local city pages.
Mapped populated places
8
These counts use a stricter populated-place filter so the main lists stay focused on real city and town pages.
Illinois counties
102
Open related pagesLargest city
MonticelloPopulation 5,557
Top linked places
Quick Facts about Piatt County
| Population | 16,355 (2020) |
| Country | United States of America |
| State | Illinois (United States) |
| Area | 1140 km2 |
| Water as percent of area | 0.06% |
| Land as percent of area | 99.94% |
| Latitude & Longitude | 40.0104,-88.5911 |
| Named for | James A. Piatt |
| Altitude | 689 feet / 210 meters |
| Capital | Monticello |
| Establishment | January 01, 1841 |
| Time Zone | America/Chicago |
| Local time | 12:57:07 (16th April 2026) |
| Density | 14 Pop. per km² as of 2020 |
| Population growth | -2.29% (2010-2020) |
| Weather | 78℉ Chance Rain Showers 7-days weather |
Geography
Piatt County is located at 40°0'37"N 88°35'28"W (40.0103700, -88.5910900). It has 4 neighbors: Douglas County, Moultrie County, Champaign County and De Witt County.
Piatt County map
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The largest city of Piatt County is Monticello with a population of 5,557. Other cities include, Bement population 1,661, Blue Ridge population 1,416, Cerro Gordo population 1,337 and Mansfield population 939. See all Piatt County cities & populated places.
Piatt County Populated Places
Cities, towns, neighborhoods & other populated places in Piatt County.
| City Name | Population | Title |
|---|---|---|
| Monticello | 5,557 | City in Piatt County, Illinois, United States |
| Bement | 1,661 | City in Illinois, United States of America |
| Blue Ridge | 1,416 | Unincorporated community in Illinois |
| Cerro Gordo | 1,337 | Human settlement in Illinois, United States of America |
| Mansfield | 939 | Human settlement in Illinois, United States of America |
| Hammond | 478 | Village in Illinois |
| De Land | 423 | Village in Piatt County, Illinois, United States |
| Cisco | 242 | Village in Piatt County, Illinois, United States |
Weather
A chance of rain showers. Partly sunny, with a high near 78.
7-Day ForecastOfficial website of Piatt County
Official WebsiteDemographics
According to census records, the population of Piatt County decreased by 2.29% in 10 years.
| Year | Population | % Change | Method |
|---|---|---|---|
| 2010 | 16,729 | - | census |
| 2011 | 16,679 | -0.3% | estimation process |
| 2012 | 16,501 | -1.08% | estimation process |
| 2013 | 16,429 | -0.44% | estimation process |
| 2014 | 16,409 | -0.12% | estimation process |
| 2015 | 16,350 | -0.36% | estimation process |
| 2016 | 16,524 | 1.05% | estimation process |
| 2017 | 16,422 | -0.62% | estimation process |
| 2018 | 16,366 | -0.34% | estimation process |
| 2019 | 16,344 | -0.13% | estimation process |
| 2020 | 16,355 | 0.07% | estimation process |
People born in Piatt County (1)
Emeritus Professor and Emeritus Curator of Insects at the Museum of Zoology of the University of Michigan in Ann Arbor, Michigan, USA Richard D. Alexander was born in Piatt County
Illinois Other Counties (more counties)
| County Name | Population | Title |
|---|---|---|
| Cook County | 5,108,284 | County in Illinois, United States |
| Chicago | 2,677,643 | The third most populous city in the United States and the center of the Chicago metropolitan area. |
| DuPage County | 917,481 | County in Illinois, United States |
| Lake County | 693,593 | County in Oregon, United States |
| Will County | 688,726 | County in Illinois, United States |
| Kane County | 531,010 | County in southern Utah, United States |
| McHenry County | 305,888 | County in Illinois, United States |
| Winnebago County | 281,295 | County in Illinois, United States |
| Madison County | 262,635 | County in Montana, United States |
| Saint Clair County | 258,046 | The County of St. |
| Champaign County | 209,192 | County in Illinois, United States |
| Aurora | 196,383 | The second most populous city in Illinois. |
| Sangamon County | 193,882 | County in Illinois, United States |
| Peoria County | 177,652 | County in Illinois, United States of America |
| McLean County | 171,256 | County in North Dakota, United States |
| Naperville | 147,986 | The second most populous city in Illinois. |