How many people live in the ?

Updated Mar. 4, 2026Refreshed annually
In 2024 there were 100,700 people in the Decatur, IL area. That makes the Decatur, IL metropolitan statistical area the 363rd populous metro area in the US. It is home to 0.03% of the nation's population.

101K

population of Decatur, IL area (2024)

0.03%

Decatur, IL area share of US population (2024)
Between 2010 and 2024, the population of the Decatur, IL area decreased from 110,800 to 100,700—a 9.1% decrease. During that same period, the US population grew 9.9%.

About 100,700 people lived in the Decatur, IL area in 2024.

Population estimates of the Decatur, IL Metro Area, 2010–2024

What are the age demographics of the Decatur, IL area?

About 21.9% of the Decatur, IL area's population in 2024 was aged 65 years or older, higher than the 18% share in the nation overall. Children (under 18) account for 22.6% of the Decatur, IL area population, above the 21.6% population share of children nationwide.

A higher share of the Decatur, IL area population is 65 and older than the US overall.

Population share by age group in Decatur, IL Metro Area and the US overall (2024)

What is the racial and ethnic makeup of the Decatur, IL area?

Non-Hispanic Black or African American residents make up 18.6% of the Decatur, IL area population, higher than the national share of 12.6%. Non-Hispanic white residents make up 73% of the population, higher than the national share of 57.5%.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.

A lower share of the Decatur, IL area population is Hispanic than the US overall.

Population share by race and ethnicity in Decatur, IL Metro Area and the US overall (2024)

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Methodology

USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.

The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.

Page sources

USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.