Jurisdiction directory

Missouri home project permits by county

Many Missouri households live outside city limits, where the county building department — not a city — issues the permit. 8 Missouri counties, covering the state's largest jurisdictions, are inventoried here.

Model reviewed August 2026

Counties covered

largest jurisdictions first

Municipalities tracked

in Missouri

Population covered

3.4M

residents in listed counties

Code basis

Local

Local adoption of the IRC; no statewide residential code

Featured counties

The largest and most active permit jurisdictions in the state.

St. Louis County County1,000,000 residents · seat Clayton Jackson County718,000 residents · seat Kansas City St. Charles County411,000 residents · seat St. Charles Greene County300,000 residents · seat Springfield St. Louis City County293,310 residents · seat St. Louis Clay County258,000 residents · seat Liberty Jefferson County229,000 residents · seat Hillsboro Boone County186,000 residents · seat Columbia

All Missouri counties we cover

8 counties, largest first.

St. Louis County CountySeat: Clayton · 1,000,000 residents Jackson CountySeat: Kansas City · 718,000 residents St. Charles CountySeat: St. Charles · 411,000 residents Greene CountySeat: Springfield · 300,000 residents St. Louis City CountySeat: St. Louis · 293,310 residents Clay CountySeat: Liberty · 258,000 residents Jefferson CountySeat: Hillsboro · 229,000 residents Boone CountySeat: Columbia · 186,000 residents

Sources

Sources & verification

Missouri Division of Fire Safety

Model vintage August 2026. The links above are the issuing agencies' own pages — we publish them so you can confirm the current rule yourself, not as evidence that each fact on this page was re-checked with them today. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing, not quotes. Permit rules change; confirm with the building department before starting work.