Alexander County (county seat: Cairo) covers 236 square miles with a population of 5240. Official county website: alexandercounty.illinois.gov. This page summarizes the verified building-regulation posture of unincorporated Alexander County land; the full 10-dimension scorecard with every source receipt lives on its Freedom Map card.
No countywide zoning ordinance found; the county administers a Subdivision Ordinance + floodplain (flood-damage-prevention) permitting rather than a residential building code — outside the mapped floodway, unincorporated building is largely permit-free (IL 815 ILCS 670 contract-code default).
The claim above is source-verified (official statute/county documents; URL, direct quote, and date on the full card). Method: how we verify.
No county's freedom erases state law: septic/wastewater permitting (health authority), well permits and water rights (state engineer/DNR), floodplain rules with federally connected financing, and — in some states — state-run electrical inspections. The full card details which of these bite in Alexander County and how hard.
The score describes unincorporated county land only. Inside Alexander County, incorporated municipalities set their own, usually stricter, rules — including: Cairo (county seat), Tamms, McClure, Thebes, Olive Branch-area villages set their own rules; the Alexander-Cairo Port District and levee/drainage districts exercise separate authority (70 ILCS 1801).. Land inside town limits follows town code.
Building rules are the first question people ask about Alexander County — and the easiest one to answer. They're rarely the one that decides it. The full card grades all ten dimensions, every claim quoted from the county's own code.
What the Alexander County card answers that this page doesn't:
It's a real map. Click any county in the country and see how it grades — that part costs nothing, and you can compare Alexander County against its neighbors before you spend a dollar.
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Last verified 2026-07-10 · Not legal advice — confirm current rules with the county, the state, and a professional before buying or building.