Fieldon is a village in Jersey County, Illinois, United States. As of the 2020 census, the village had a total population of 176.

The town's original founding was in the 1830's by a man known as John Field. It is believed that the town grew as a trading post for travelers on the Illinois River. When the construction of the Chicago, Burlington and Quincy Railroad made its way through the neighboring city of Jerseyville in 1853 it brought even more businesses to the area. During the Civil War Fieldon was a known stop for the Underground Railroad. The town also sent troops for the 122nd Illinois Infantry Regiment. In the early 1900s Feildon saw a boom in industry which included canneries, sawmills, and more. After the Great Depression the town saw its economy shift towards agriculture. Feildon saw a peak population in the 1980's at 299 individuals and has since seen a steady decline.

Fieldon is located at 39°6′29″N 90°30′0″W / 39.10806°N 90.50000°W / 39.10806; -90.50000 (39.108184, -90.500048).

According to the 2010 census, Fieldon has a total area of 0.2 square miles (0.52 km), all land.

Historical population

Census	Pop.	Note	%±
1880	298		—
1890	292		−2.0%
1900	259		−11.3%
1910	227		−12.4%
1920	248		9.3%
1930	232		−6.5%
1940	217		−6.5%
1950	250		15.2%
1960	239		−4.4%
1970	257		7.5%
1980	299		16.3%
1990	277		−7.4%
2000	271		−2.2%
2010	239		−11.8%
2020	176		−26.4%
U.S. Decennial Census

As of the census of 2000, there were 271 people, 103 households, and 79 families residing in the village. The population density was 1,362.1 inhabitants per square mile (525.9/km). There were 110 housing units at an average density of 552.9 per square mile (213.5/km). The racial makeup of the village was 100.00% White. Hispanic or Latino of any race were 1.11% of the population.

There were 103 households, out of which 31.1% had children under the age of 18 living with them, 66.0% were married couples living together, 5.8% had a female householder with no husband present, and 23.3% were non-families. 18.4% of all households were made up of individuals, and 10.7% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.04.

In the village, the population was spread out, with 26.2% under the age of 18, 5.9% from 18 to 24, 29.5% from 25 to 44, 21.8% from 45 to 64, and 16.6% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 102.2 males. For every 100 females age 18 and over, there were 100.0 males.

The median income for a household in the village was $38,393, and the median income for a family was $40,156. Males had a median income of $32,250 versus $19,583 for females. The per capita income for the village was $14,811. None of the families and 0.8% of the population were living below the poverty line.

Fieldon is served by the public K-12 Jersey Community Unit School District 100. Fieldon Elementary School was located in the village until 2012, when it was permanently closed due to district realignment.