Grantfork, Illinois Demographics & Population 2026

A note before these figures: with a population of 459, Grantfork's ACS estimates come from a small number of survey responses and carry wide margins of error. Individual percentages below — particularly rates that round to 0% or 100% — are approximations, not precise measurements. See data.census.gov for the published margins of error.

Population Overview

Grantfork is a small community located in Illinois, within Madison County. The total population is 459. It ranks as the 962nd most populous out of 1,445 Census-designated places in Illinois.

Age Demographics

The median age in Grantfork is 35.8 years. This is 8% lower than the state median of 39.0 years. With 29.2% of the population under 18, Grantfork has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The median household income in Grantfork is $95,625. This is 15% higher than the state median of $83,390. It is also 18% higher than the national median of $80,734. The poverty rate stands at 13.3%. This is 13% higher than the state poverty rate of 11.8%. The unemployment rate is 7.1%. This is 21% higher than the state rate of 5.8%. The median home value is $167,900. Housing costs are 36% lower than the state median of $263,300. With a home-value-to-income ratio of just 1.8x, Grantfork is one of the most affordable housing markets in the area. 98.2% of occupied housing units are owner-occupied. This homeownership rate is 46% higher than the state average of 67.1%.

Race & Ethnicity

Grantfork has a predominantly White (non-Hispanic) population, comprising 96.1% of all residents. Asian residents account for 0.7%. The White (non-Hispanic) population is significantly higher than the state average (96.1% vs 58.1%). The Hispanic or Latino population (0.4%) is well below the state average of 18.8%. The Asian population (0.7%) is well below the state average of 5.9%.

Education

47.3% of residents aged 25 and older hold a bachelor's degree or higher. This places Grantfork in the top 10% of all cities in the state for educational attainment. This is 25% higher than the state rate of 37.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 98.6%.

Data Sources & Methodology

All demographic data for Grantfork, Illinois is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against Illinois state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 1,445 Census-designated places in Illinois. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.