Colorado Zoning Report: How Zoning Works in Denver, the Front Range, and Colorado Counties

Colorado zoning is local, layered, and changing fast. Home-rule cities write their own codes, counties zone the land outside them, and since 2024 the state has stepped in on accessory dwelling units, parking, and transit-area density. This report explains how the pieces fit, how to read the Denver Zoning Code's unusual labels, and how to look up any Colorado parcel.

Who zones what in Colorado

• Home-rule municipalities (Denver, Colorado Springs, Aurora, Fort Collins, Boulder, and most Front Range cities) adopt their own zoning codes under the state constitution and can differ from state statute on local matters.
• Statutory municipalities zone under the state's municipal zoning statutes.
• Counties zone unincorporated land under the county planning statutes. Colorado's 35-acre rule, which exempts parcels of 35 acres or more from subdivision review, is why many rural county districts are built around 35-acre minimums.
• The state does not zone, but 2024 legislation now sets minimum standards that larger cities must meet on several housing issues.

Which code applies depends on whether the parcel is inside a city's limits. The county assessor's record and the county GIS map show the jurisdiction.

Reading the Denver Zoning Code

Denver's code, adopted in 2010, labels every zone district by neighborhood context, then by building form, then by intensity. A district like U-SU-C reads as Urban context, Single Unit, lot size C; C-MX-5 is Urban Center context, Mixed Use, five stories; E-TU-B is Urban Edge context, Two Unit, lot size B; I-MX-3 is Industrial context, Mixed Use, three stories; I-A and I-B are the general and heavy industrial districts.

The contexts are Suburban (S), Urban Edge (E), Urban (U), General Urban (G), Urban Center (C), Downtown (D), Industrial (I), Campus (CMP), and Open Space (OS). The middle letters give the form: SU (single unit), TU (two unit), TH (townhouse), RH (row house), MU (multi unit), MX (mixed use), RX (residential mixed use), MS (main street), CC (commercial corridor). The suffix is a lot-size letter for residential districts or a maximum number of stories for mixed-use districts.

Denver also carries many legacy PUDs (see our PUD explainer) and overlays such as design overlays and the Uses Overlay districts. The city allowed accessory dwelling units in all residential zone districts in 2024, and its "Expanding Housing Affordability" rules attach affordability requirements to larger residential projects.

Official Denver map: Denver Zoning Map.

Other Front Range codes

• Colorado Springs adopted a new unified development code in 2023 with renamed districts, so older references (R-1 through R-5, C-5, C-6, M-1) map onto new labels; check the current code.
• Aurora uses a conventional scheme with residential (R-1 through R-5), mixed-use, and industrial districts, and overlays around its transit stations and the airport.
• Boulder uses context-based districts (RL, RM, RH, BC, BR, IG) and some of the strictest height limits in the state.
• Fort Collins uses named districts (NC, LMN, MMN, HMN, CC, I) tied to its city plan.

The 2024 state housing laws

Colorado's 2024 legislative session changed the ground rules for larger municipalities in the state's metropolitan planning areas:

• Accessory dwelling units (HB24-1152): affected cities must allow at least one ADU on lots where single-family homes are allowed, subject to state limits on local restrictions.
• Minimum parking near transit (HB24-1304): affected cities may not impose parking minimums on multifamily and mixed-use residential projects near frequent transit.
• Transit-oriented communities (HB24-1313): affected cities must plan for and zone minimum housing densities in areas near transit stations and corridors.
• Occupancy limits (HB24-1007): local governments may not limit the number of unrelated people who can live together based on familial status.

Compliance deadlines run through 2025 and later, and cities are amending their codes to meet them. When a Colorado map still shows a single-family district, the state law may already allow more than the label suggests.

County zoning outside the cities

County districts typically include agricultural districts with large minimum lots (A-1, A-2, A-35 style labels), rural residential, and limited commercial and industrial districts along highways. Counties on the Front Range edge (Weld, Adams, Arapahoe, Douglas, El Paso) hold most of the region's development land, and their comprehensive plans and utility service areas tell you which agricultural parcels are realistic candidates for annexation and rezoning. Our A-1 explainer covers agricultural districts in more detail.

How to look up any Colorado parcel

1. Find the jurisdiction on the county assessor's record or GIS map.
2. Open that jurisdiction's official zoning map (Denver's is linked above; other cities publish theirs on the planning department's site).
3. Note the full district label and any overlay or PUD.
4. Read the district's use table and standards in the current code, and check whether the 2024 state laws add permissions.
5. Confirm with planning staff, in writing for a transaction.

In Plotzy, Colorado parcels carry the jurisdiction's zoning designation, so a search across Denver, Aurora, and the surrounding counties by district and lot size is one query, with the owner of record on every result. Zoning AI can answer district questions from the codes it has ingested with the section cited.

Frequently asked questions

Who controls zoning in Colorado?

Cities zone land inside their limits, counties zone unincorporated land, and home-rule cities write their own codes. Since 2024, state law sets minimum standards on accessory dwelling units, parking near transit, transit-area density, and occupancy limits for larger municipalities.

What does U-SU-C mean in Denver?

Urban neighborhood context, Single Unit building form, lot size C. Denver's zone districts combine a context letter, a building form, and a lot size or story count.

Can I build an ADU in Colorado?

In Denver, yes, in all residential zone districts as of 2024. Under HB24-1152, other larger Front Range cities must allow at least one ADU on single-family lots, subject to implementation deadlines.

What is the 35-acre rule in Colorado?

Parcels of 35 acres or more are exempt from county subdivision review under state law, which is why many rural county zoning districts use 35-acre minimum lot sizes.

Where do I find a Colorado zoning map?

On the planning department site of the city or county that has jurisdiction. Denver publishes its map at denvergov.org; counties and other cities publish theirs on their own GIS portals.