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Jurisdiction directory

Illinois home project permits by county

Many Illinois households live outside city limits, where the county building department — not a city — issues the permit. 12 Illinois counties, covering the state's largest jurisdictions, are inventoried here.

Verified August 2026

Counties covered

12

largest jurisdictions first

Municipalities tracked

17

in Illinois

Population covered

9.6M

residents in listed counties

Code basis

Local

Local adoption of the IRC; statewide plumbing and energy codes apply

Highest-priority markets

Ranked by population, regulatory complexity, home-rule authority and municipal density.

Cook County5,087,000 residents · priority 75.1DuPage County933,000 residents · priority 68.3Lake County711,000 residents · priority 66.1Will County700,000 residents · priority 66Kane County517,000 residents · priority 65.6McHenry County310,000 residents · priority 61.4Winnebago County284,000 residents · priority 61Madison County264,000 residents · priority 60.6St. Clair County255,000 residents · priority 60.4Champaign County206,000 residents · priority 59.8Sangamon County195,000 residents · priority 58.9Peoria County180,000 residents · priority 58.4

All Illinois counties we cover

12 counties, largest first.

Cook CountySeat: Chicago · 5,087,000 residentsDuPage CountySeat: Wheaton · 933,000 residentsLake CountySeat: Waukegan · 711,000 residentsWill CountySeat: Joliet · 700,000 residentsKane CountySeat: Geneva · 517,000 residentsMcHenry CountySeat: Woodstock · 310,000 residentsWinnebago CountySeat: Rockford · 284,000 residentsMadison CountySeat: Edwardsville · 264,000 residentsSt. Clair CountySeat: Belleville · 255,000 residentsChampaign CountySeat: Urbana · 206,000 residentsSangamon CountySeat: Springfield · 195,000 residentsPeoria CountySeat: Peoria · 180,000 residents

Sources

Sources & verification

Last verified August 2026. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing — they are not quotes. Permit rules change; confirm with the building department before starting work.