Your zoning district is the rule that decides what you can legally do with your lot — whether you can add a second unit, build up, run a business, or only keep a single-family house. It is public record, tied to the parcel, and you can find it from your address in a couple of minutes in both Columbus and Chicago.
Columbus (Franklin County)
Columbus zoning comes from the City of Columbus. The city is in the middle of Zone In, a ground-up rewrite of a zoning code that had not been comprehensively updated in decades — so a parcel can carry both its current district and, along the major corridors already adopted, a new Zone In district. That matters because the new code is generally more permissive about density and mixed use along corridors. Resolve your address and Civic Worth shows the district, with the Zone In status where it applies.
Chicago (Cook County)
Chicago zoning is a letter-and-number code — RS-3, B3-2, and so on. The letter is the family (RS single-family, RT/RM multi-unit, B business, C commercial, M manufacturing) and the number is the intensity. If that string looks cryptic, the Chicago zoning ordinance explainer breaks down every part. Search your address to get the current district for your specific parcel.
What the district actually controls
Across both cities, the zoning district sets three things: the use (can this be a shop, an apartment, a factory), the bulk (how many units, how tall, how much floor area, the setbacks), and often parking. It is the first gate every building permit passes through. It does not, by itself, tell you about deed restrictions, historic-district rules, or a Planned Development overlay — those can add constraints on top.
Check the current district — it changes
Zoning is rewritten and amended constantly: Columbus through Zone In, Chicago through aldermanic zoning changes and evolving ADU rules. An old PDF or a neighbor’s recollection is not reliable. Search your address above for the current district, then open your city’s zoning map — Columbus or Chicago — to see the pattern around you.
Source: City of Columbus and City of Chicago zoning districts (public records), resolved to the parcel. Zoning determinations for permits are made by the city; confirm with the relevant planning department before relying on it.