Fieldon is a village in Jersey County, Illinois, United States. As of the 2010 census, the village had a total population of 239. The village's current mayor is Betty Duggan.
Fieldon is located at 39°6′29″N 90°30′0″W (39.108184, -90.500048).
According to the 2010 census, Fieldon has a total area of 0.2 square miles (0.52 km2), all land.
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 people per square mile (523.2/km²). There were 110 housing units at an average density of 552.9 per square mile (212.4/km²). 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.