Piatt County is a county in Illinois, United States, on the flat prairie of east-central Illinois between the Bloomington-Decatur-Champaign triangle. It had a population of 16,673 at the 2020 census and covers 439 square miles (1,140 km2) centred near 40°01′N 88°35′W.
Monticello is the county seat, and its postal code is 61856. The county has one city, six incorporated villages, and several unincorporated communities spread across eight civil townships. Piatt County sits in the Central time zone and is part of the Champaign-Urbana metropolitan statistical area.
Towns & Villages in Piatt County
Piatt County has one incorporated city, six incorporated villages, and a scatter of unincorporated crossroads communities and former settlements. The table below uses City · seat for Monticello, Village for the six incorporated villages, and Unincorp. for places with no city or village government of their own.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Monticello | City · seat | Monticello | — | 61856 |
| Atwood | Village | Blue Ridge | — | — |
| Bement | Village | Bement | — | 61813 |
| Cerro Gordo | Village | Cerro Gordo | — | 61818 |
| Cisco | Village | Cerro Gordo | — | 61830 |
| De Land | Village | Goose Creek | — | 61839 |
| Hammond | Village | Unity | — | 61929 |
| Mansfield | Village | Sangamon | — | 61854 |
| Amenia | Unincorp. | Willow Branch | — | — |
| Blue Ridge | Unincorp. | Blue Ridge | — | — |
| Bodmann | Unincorp. | — | — | — |
| Burrowsville | Unincorp. | — | — | — |
| Centerville | Unincorp. | — | — | — |
| Combs | Unincorp. | — | — | — |
| Galesville | Unincorp. | Monticello | — | — |
| Harris | Unincorp. | — | — | — |
| La Place | Unincorp. | Sangamon | — | 61936 |
| Lintner | Unincorp. | — | — | — |
| Lodge | Unincorp. | Unity | — | — |
| Mackville | Unincorp. | — | — | — |
| Milmine | Unincorp. | Bement | — | 61855 |
| Piatt | Unincorp. | — | — | — |
| Pierson | Unincorp. | Goose Creek | — | — |
| Voorhies | Unincorp. | Willow Branch | — | — |
| White Heath | Unincorp. | Monticello | — | 61884 |
Cerro Gordo straddles the Piatt/Macon county line, and its village limits and post office serve residents on both sides. White Heath and Galesville sit close together along the Sangamon River northwest of Monticello and are sometimes confused with each other on older maps.
Townships
Piatt County is divided into eight civil townships. Per-township 2020 population breakdowns are not published in a form this page can verify, so the table below lists each township’s main settlements rather than a population figure.
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| Monticello | — | Monticello, White Heath, Galesville |
| Bement | — | Bement, Milmine |
| Cerro Gordo | — | Cerro Gordo, Cisco |
| Blue Ridge | — | Atwood, Blue Ridge |
| Sangamon | — | Mansfield, La Place |
| Goose Creek | — | De Land, Pierson |
| Unity | — | Hammond, Lodge |
| Willow Branch | — | Amenia, Voorhies |
ZIP Codes
- 61856 — Monticello (also serves Galesville)
- 61813 — Bement (also serves Milmine)
- 61818 — Cerro Gordo
- 61830 — Cisco
- 61839 — De Land
- 61854 — Mansfield
- 61855 — Milmine
- 61884 — White Heath
- 61929 — Hammond
- 61936 — La Place
Atwood residents use a Piatt/Douglas County ZIP shared with the neighboring county, and several unincorporated crossroads such as Bodmann, Combs, and Lintner have no post office of their own and are served by the nearest town’s ZIP.
Geography
Piatt County lies on level to gently rolling prairie drained by the Sangamon River, which crosses the county from northeast to southwest through Monticello, and by the Sangamon’s Friends Creek tributary in the county’s east. Nearly all of the county’s 439 square miles is farmland; only 0.3 square miles is water.
Piatt County borders McLean County to the north, Champaign County to the east, Douglas County to the southeast, Moultrie County to the south, Macon County to the southwest, and De Witt County to the west. Champaign, McLean, and Moultrie are linked here as Champaign County, McLean County, and Moultrie County; Douglas and Macon have separate state-suffixed pages at Douglas County, Illinois and Macon County, Illinois. De Witt County has no live page on this site to link to.
Demographics
Piatt County had 16,673 residents at the 2020 census, spread over 439 square miles for a density of roughly 38 people per square mile. Monticello, the county seat, is by far the largest community, followed by Bement. Median household income in the county has historically run close to or slightly above the Illinois median of $80,306, reflecting the area’s mix of farm ownership and commuter households working in Champaign-Urbana and Decatur.
Economy & Local Life
Corn and soybean farming dominates the local economy, as it does across most of east-central Illinois’s prairie counties. Monticello is home to Allerton Park & Retreat Center, a University of Illinois-owned estate and public garden on the Sangamon River, and to the Monticello Railway Museum, which runs excursion trains on former Illinois Central trackage. Many county residents commute to jobs in Champaign-Urbana or Decatur.
History
Piatt County was organized in 1841 from parts of Macon and De Witt counties. George Haworth, a Quaker, is credited as the area’s first settler, followed by James Martin, Abraham Hanline, Solomon Carter, and William Cordell. The county is named for James A. Piatt, an early settler who, according to local tradition, won the naming right over fellow settler Jesse Warner in a coin toss.
Getting There
Interstate 72 crosses Piatt County east-west through Monticello, connecting it to Champaign-Urbana to the east and Decatur to the west. Illinois Routes 10 and 105 provide the main local connections between the county’s towns.
- Champaign — 24 miles east
- Decatur — 22 miles southwest
- Bloomington — 35 miles north
- Springfield — 65 miles southwest
The nearest commercial airport is University of Illinois Willard Airport in Savoy, about 25 miles east of Monticello.
Frequently Asked Questions
Where is Piatt County?
Piatt County is in east-central Illinois, between Champaign-Urbana and Decatur.
What is the population of Piatt County?
Piatt County had a population of 16,673 at the 2020 census.
How big is Piatt County?
Piatt County covers 439 square miles (1,140 km2), of which 0.3 square miles is water.
What is the county seat of Piatt County?
Monticello is the county seat.
How many towns are in Piatt County?
Piatt County has one city, six incorporated villages, and about a dozen unincorporated communities across eight townships.
What ZIP codes are in Piatt County?
Piatt County’s ZIP codes include 61856 (Monticello), 61813 (Bement), 61818 (Cerro Gordo), 61830 (Cisco), 61839 (De Land), 61854 (Mansfield), 61855 (Milmine), 61884 (White Heath), 61929 (Hammond), and 61936 (La Place).
Why is Piatt County named after James Piatt?
Local tradition holds that early settlers James A. Piatt and Jesse Warner, both active in organizing the new county in 1841, settled the naming question with a coin toss, which Piatt won.
More counties in this state: Towns and villages in Illinois.