Which county in Illinois has the lowest flood risk?

McDonough has the lowest flood risk in Illinois, at 14.6.

What is the flood risk in McDonough?

McDonough is ranked #1 in Illinois for flood risk, at 14.6.

What are the top counties in Illinois for flood risk?

McDonough (14.6), then Schuyler (21.3), and Brown (22.0). The full top 25 is in the table on this page.

How is this flood risk ranking calculated?

Counties in Illinois are ranked by flood risk (FEMA National Risk Index, FEMA NRI v1.20), lowest first. Values describe the county, not an individual property. Source vintage is shown on the page.

How does Illinois compare to the rest of the US for flood risk?

This list is Illinois only. See the national ranking of the lowest counties for flood risk at hearthmap.app/best/lowest-flood-risk.

Lowest Flood Risk Counties in Illinois (2026)

Lowest counties for flood risk in Illinois

Top 25 of 102 counties with data.

Ranked by flood risk (FEMA National Risk Index, FEMA NRI v1.20), lowest first.

Lowest counties for flood risk in Illinois

Rank	County	Value
01	McDonough14.6 County page
02	Schuyler21.3 County page
03	Brown22.0 County page
04	Warren24.2 County page
05	Greene27.4 County page
06	Hancock29.6 County page
07	Mercer32.2 County page
08	Rock Island32.7 County page
09	Knox35.3 County page
10	Scott40.1 County page
11	Adams44.2 County page
12	Jersey44.4 County page
13	Henry46.9 County page
14	Christian49.3 County page
15	Peoria52.6 County page
16	McLean52.6 County page
17	Hamilton54.1 County page
18	Vermilion54.1 County page
19	Macon54.5 County page
20	Monroe56.4 County page
21	Cass57.8 County page
22	DuPage58.3 County page
23	Fulton58.8 County page
24	Whiteside58.8 County page
25	Pike59.2 County page

How this ranking works

This page ranks Illinois counties by flood risk, sorted so the lowest places appear first. Click any county to see its housing, schools, crime, and demographics in detail.

For flood risk, a lower value is generally more favorable, so the top of the list is the lowest. Want to weigh flood risk against schools, taxes, commute, and more at once? Use the live map to build a custom match.

Data comes from public sources. Source attribution and the exact data vintage are shown above and on the full map of flood risk.

Frequently asked questions

Which county in Illinois has the lowest flood risk?: McDonough has the lowest flood risk in Illinois, at 14.6.
What is the flood risk in McDonough?: McDonough is ranked #1 in Illinois for flood risk, at 14.6.
What are the top counties in Illinois for flood risk?: McDonough (14.6), then Schuyler (21.3), and Brown (22.0). The full top 25 is in the table on this page.
How is this flood risk ranking calculated?: Counties in Illinois are ranked by flood risk (FEMA National Risk Index, FEMA NRI v1.20), lowest first. Values describe the county, not an individual property. Source vintage is shown on the page.
How does Illinois compare to the rest of the US for flood risk?: This list is Illinois only. See the national ranking of the lowest counties for flood risk at hearthmap.app/best/lowest-flood-risk.