# Sign Regulations in Thornton, Colorado

Sign permit rules, size and height limits, setbacks, and ordinance citations for Thornton, Colorado, compiled by PermitPal from the jurisdiction's published municipal code.

- **Jurisdiction:** Thornton, Colorado (CO)
- **Canonical page:** https://permitpal.io/sign-regulations/colorado/thornton
- **Data last verified:** 2025-05-09
- **Source:** [municode municipal code](https://library.municode.com/CO/Thornton/codes/Code_of_Ordinances?nodeId=CO_CH18DECO_ARTVIISI)

## At a glance

Thornton, Colorado regulates 17 sign types across 5 zoning districts. Canopy Signs in the Agricultural zoning district are capped at Controlled by canopy structure tall and 60 square feet (total for all signs on canopy), with a Controlled by canopy structure setback (Sec. Sec. 18-731, Table 18-731.1). Most commercial signs in Thornton require a permit.

## Sign rules by zoning district (5 zones)

| Zoning District | Sign Types Regulated | Max Height | Max Area | Permit Required |
| --- | --- | --- | --- | --- |
| Agricultural | 8 | 30 feet or the building height, whichever is less | Developed: 72 sq ft; Undeveloped: 120 sq ft | — |
| Neighborhood Service (NS), Community Retail (CR), Regional Commercial (RC), Business Park (BP), City Center (CC), Office/Institutional (OI), Employment Center (EC), Mixed Use (MU), Transit Oriented Development (TOD), Eastlake Business (EB), Eastlake Service (ES), Eastlake Office (EO), Eastlake TOD (ETD), Industrial (I) | 12 | 30 ft or bldg height, whichever less | Developed: See Table 761.1 (e.g., CR/RC/BP/CC/TOD/I: <25k sqft: 60 sq ft per bldg user/tenant; 25k-100k: 105 sq ft per user/tenant; 100k+: 230 sq ft per user/tenant); Undeveloped: CR/RC/BP/CC/TOD/I: 250 sq ft; NS/MU/OI/EC/EB/ES/EO/ETD: 150 sq ft. | — |
| Residential Estate, Single-Family Detached, Single-Family Attached, Multifamily, Manufactured Home, Eastlake Residential | 4 | Banners - controlled by structure; Freestanding/feather flag: 20 ft; Large balloon: 50 ft. | Developed: 72 sq ft; Undeveloped: 120 sq ft | — |
| Planned Development (PD) District, Preservation Revitalization (P/R) District (residential and/or commercial), Mineral Conservation (MC) District | 1 | — | — | — |
| General Regulations For All Zones | 4 | Flagpole max 35 ft or building height, whichever less | Lots <10k sqft: one flag up to 15 sq ft; 10k-100k: flags up to 50 sq ft, max 2; 100k+: flag up to 100 sq ft, max 3. | — |

## Zone-by-zone sign requirements (sample of 3 of 5 zones)

### Agricultural

| Sign Type | Max Height | Max Area | Max Width | Setback | Signs Allowed | Location | Permit Required | Ordinance Citation |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Canopy Sign | Controlled by canopy structure | 60 square feet (total for all signs on canopy) | — | Controlled by canopy structure | Any number, subject to total area | On canopy | — | Sec. 18-731, Table 18-731.1 |
| Wall Sign | Controlled by wall on which sign is attached | Greater of 60 sq ft or 8% of area of largest elevation of the main building(s) on the lot; For high-rise: specific caps depending on stories. | — | Controlled by wall | No limit | On any elevation of building three stories or less; for taller, see specific regulations. | — | Sec. 18-735, Table 18-735.1 |
| Light Pole Banner | Must be attached below the light arm. Minimum clearance: 7 feet from bottom arm supporting the banner (except reduced if does not impede/block traffic). | 15 square feet per banner | — | Minimum clearance: 7 feet to bottom arm; No minimum setback otherwise. | See sign size restrictions | On private property, on light poles (may project up to 30 inches into ROW, not block traffic). | — | Sec. 18-742, Table 18-742.1 |
| Monument Sign | 6 feet | 42 square feet (legible from right-of-way) | — | — | Two per zone lot | In landscaped area, similar to surroundings | — | Sec. 18-743, Table 18-743.1 and (a)(1) |
| Pole Sign | 30 feet or the building height, whichever is less | 40 square feet | — | — | One per zone lot (90+ ft frontage) | — | — | Sec. 18-744, Table 18-744.1 |
| Electronic Sign | As monument or wall sign regulations | 50% of total allowed monument sign area or 30 sq ft for wall signs | — | As monument or wall sign | One per zone lot, plus 1 adtl. for large development | Monument or wall sign (not pole, not billboard) | — | Sec. 18-750, Table 18-750.1 and (a)(3) |
| Special Event Sign | Banners - structure controlled; Freestanding/feather flags: 20 ft; Large balloons: 50 ft. | Freestanding/banners: 60 sq ft; Large/undev: up to 120 sq ft. Balloons: unlimited for small; one large or inflatable device. | — | 10 ft for banners/freestanding/feather; Large balloon etc: setback = height | 4 sign permits per year | Private property with 10 ft setback for banners, freestanding, feather flags; others: setback = height | — | Sec. 18-760, Table 18-760.1 |
| Temporary Sign | Developed: 6 ft; Undeveloped: 10 ft; Banners: height controlled by structure | Developed: 72 sq ft; Undeveloped: 120 sq ft | — | 5 ft or sign height, whichever is larger; 25 ft from intersecting ROW | Any, per area/lot max | — | — | Sec. 18-761, Table 761.1 |

### Neighborhood Service (NS), Community Retail (CR), Regional Commercial (RC), Business Park (BP), City Center (CC), Office/Institutional (OI), Employment Center (EC), Mixed Use (MU), Transit Oriented Development (TOD), Eastlake Business (EB), Eastlake Service (ES), Eastlake Office (EO), Eastlake TOD (ETD), Industrial (I)

| Sign Type | Max Height | Max Area | Max Width | Setback | Signs Allowed | Location | Permit Required | Ordinance Citation |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Canopy Sign | Controlled by canopy structure | 60 square feet | — | Controlled by canopy structure | Any (cumulative area limit) | On canopy | — | Sec. 18-731, Table 18-731.1 |
| Cylinder Sign | 10 feet | 12 square feet | — | Controlled by wall | One | On wall of nonresidential building | — | Sec. 18-732, Table 18-732.1 and (a) |
| Projecting Sign | Max height of first floor elevation; Minimum 7 ft clearance above grade. | Total for all projecting signs = 50% of permitted wall sign area. Combined total of projecting/wall signs = 100% of wall sign maximum. | — | Controlled by wall | One per user or tenant | On wall | — | Sec. 18-733, Table 18-733.1 |
| Under-Canopy Sign | Controlled by canopy structure. Minimum 7 ft clearance bottom edge | 4 square feet | — | Controlled by canopy | 2 per user/tenant | Under canopy | — | Sec. 18-734, Table 18-734.1 |
| Wall Sign | Controlled by wall; Above 1st floor: 2 allowed, not more than 1 per elevation | Greater of 60 sq ft or 8% of area of largest building elevation, subject to high-rise caps and per elevation totals. Max single elevation: 1,000 sq ft; All elevations: 2,000 sq ft. (Large retail >300k sqft, lot >50 acres on I-25/E-470: limits not applied) | — | Controlled by wall | No limit (first floor); see formula for upper floors | Any elevation; above 1st floor, see limits | — | Sec. 18-735, Table 18-735.1 |
| Light Pole Banner | Must be attached below the light arm. Minimum 7 ft clearance from bottom arm supporting banner (except reduced as permitted) | 15 square feet per banner | — | Min 7 ft to bottom arm | See sign size restrictions | Light poles on private property (may extend max 30in into ROW if not blocking traffic) | — | Sec. 18-742, Table 18-742.1 |
| Electronic Sign | As monument or wall sign per zone | 50% of monument sign area; 30 sq ft for wall sign | — | As per wall/monument sign regulation | One per lot, plus 1 adtl. for large dev | Monument or wall (not billboard/pole) | — | Sec. 18-750, Table 18-750.1 and (a)(4),(a)(5) |
| Billboard Sign | 25 ft (8 ft minimum from ground within 1,000 ft of intersection ROW) | 300 sq ft | — | 25 ft; 300 ft from intersection ROW | Any number, but min spacing rules | Undeveloped property only off-site freestanding; must be removed on development/redevelopment | — | Sec. 18-741, Table 18-741.1 and (a) |

### Residential Estate, Single-Family Detached, Single-Family Attached, Multifamily, Manufactured Home, Eastlake Residential

| Sign Type | Max Height | Max Area | Max Width | Setback | Signs Allowed | Location | Permit Required | Ordinance Citation |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Monument Sign | 6 ft | 42 sq ft (legible from ROW) | — | — | Two per zone lot | In landscaped area, similar to surroundings | — | Sec. 18-743.1 |
| Electronic Sign | As for monument or wall sign | 50% of allowed monument sign area; or 30 sq ft for wall sign | — | — | One per zone lot, plus one for large development | On monument or wall, not pole or billboard | — | Sec. 18-750 Table 18-750.1 and (a)(3) |
| Special Event Sign | Banners - controlled by structure; Freestanding/feather flag: 20 ft; Large balloon: 50 ft. | Freestanding/banners: 60 sq ft; Balloons: unlimited small; one large or inflatable | — | 10 ft (banners, freestanding, feather flag); Balloon/inflatables: setback = height | 4 permits/yr | 10 ft setback for banners/freestanding/feather flag; large balloon/inflatables: setback = height | — | Sec. 18-760, Table 18-760.1 |
| Temporary Sign | Developed: 6 ft; Undeveloped: 10 ft; Banners: controlled by structure | Developed: 72 sq ft; Undeveloped: 120 sq ft | — | 5 ft or height of sign (whichever greater) and 25 ft from intersecting ROW | Any (area capped) | — | — | Sec. 18-761, Table 761.1 |

## Prohibited signs in Thornton

- Erect, maintain, or continue the use of any sign with an image or message which is not within the protection of the Colorado Constitution and the First Amendment to the U.S. Constitution because of the harm that they cause to minors, or to individuals or to the community.
- Erect, maintain, or continue the use of any sign that is not specifically permitted or exempted from this article, or is an animated sign, roof sign, building wrap sign, or searchlight.
- Erect, maintain, or continue the use of any sign in, over, or extending into any public rights-of-way, or to paint or affix any sign on or to any object within any public rights-of-way, except as permitted in this article or in Chapter 70 of this Code.
- Erect, maintain, or continue the use of any sign within a visibility triangle as defined in Section 18-567 unless otherwise exempted by this article.
- Erect, maintain, or continue the use of any sign that causes a traffic hazard because of glare, focus or intensity of illumination.
- Erect, maintain, or continue the use of any sign that blocks a doorway or opening which is required for entrance to or exit from any building, structure, parking lot or driveway by the International Building Code adopted in Section 10-151, the International Fire Code adopted in Section 10-160, or any development permit.
- Erect, maintain, or continue the use of any sign on any fence, or paint or affix any sign on, or to, a fence set back five feet or less from the city's rights-of-way, except as specifically permitted by this article.
- Erect, maintain, or continue the use of any sign on any property without the written permission of the property owner or person in lawful possession of the property.
- Erect, maintain, or continue the use of any sign or signal, marking or device that is not authorized and which purports to be, is an imitation of, or resembles but is not an official traffic control device or railroad sign or signal, within 10 feet of the edge of any street.
- Erect, maintain, or continue the use of any sign that hides from view or interferes with the visibility of any official traffic control device or railroad sign or signal.
- Erect, maintain, or continue the use of any sign attached to landscaping elements or other natural objects.
- Erect, maintain, paint, affix or continue the use of any sign on or to any other sign unless done with a valid sign permit or unless exempted from the requirement for a permit under this article.
- Fail to maintain or keep in good repair any sign, including the repairing of glass, plastic, sign face material, or sign supporting structures when missing, broken, damaged, or deteriorated.
- Place any sign on private property without the consent of the legal owner and all persons holding the right of possession and control.
- Display or maintain a nonconforming sign after it is damaged to the extent of 50 percent or more of its replacement value, poses an imminent safety hazard, or the associated use has been discontinued for six months or more.
- Erect, maintain, or continue the use of any sign that is otherwise prohibited or illegal under this article or other applicable laws.

## Signs exempt from permit in Thornton

- Official governmental signs, including but not limited to traffic control signs and devices, informational signs, temporary public notices, banners, flags, light pole banners, and any other signs required by law.
- Signs that: are installed in a location or manner which do not create a traffic hazard; are located on private property and not in any public rights-of-way; do not exceed four square feet per sign face; do not cumulatively exceed 40 square feet per zone lot; and are not prohibited or illegal signs as provided in Section 18-706 or otherwise regulated.
- Signs painted on or placed in a window.
- Flags that meet the following standards and that maintain a minimum seven foot clearance between the lowest point of the flag and grade level: On zone lots smaller than 10,000 square feet, one flag no larger than 15 square feet; On zone lots between 10,000 and 100,000 square feet, flags no larger than 50 square feet, maximum of two flags per zone lot; On zone lots larger than 100,000 square feet, flags no larger than 100 square feet, maximum of three flags per zone lot; The maximum height of a flagpole for all flags is 35 feet or the height of the building, whichever is less.
- Vehicular signs: Shall be permitted if they contain no flashing or moving elements; are permanently mounted or affixed, or magnetically attached, to the vehicle; do not project beyond the surface of the vehicle on which they are attached a distance in excess of six inches; are attached to an operable vehicle; are parked in a designated parking space, when available, when parked and visible from the public rights-of-way. Vehicular signs parked within 25 feet of an arterial or collector street shall count against the total sign area allowance for the property unless there is no other location on the property where the vehicle can be parked.
- Any sign on or constructed in association with a bus shelter or bus bench that is specifically allowed by a written contract with the city.
- Temporary decorations of any type, number, area, height, location, illumination, or animation that are located on buildings or structures so as not to conflict with or obstruct traffic regulatory devices.
- Private persons dressed in costume or displaying signs expressing messages that are within the protection of the First Amendment, subject to: signs must be held by or attended by one or more persons; signs shall not be inflatable or air-activated; persons and signs shall not visually or physically obstruct, impede or block the flow of traffic or pedestrians on streets, sidewalks or trails; not be located on a public street median or round-a-bout; not conduct sales, transfer product, or collect monies of any kind; not obstruct or impede scheduled activities.
- Any signs required to be erected by city, state, or federal law.
- Any signs not legible or intended to be read from the right-of-way or private streets.

## Sign plan & submission notes

- A sign permit is required for any sign regulated by the article unless specifically exempted in Section 18-705.
- Large developments (4 acres or more, 4 or more tenant spaces in a building, or multiple main buildings sharing parking/access in specified zones) are required to submit a large development signage plan prior to sign installation.
- The large development signage plan must include a plot plan, all building and site elements, computations of maximum total sign area, number, height, location of all present and future signs (excluding exempt signs), and must meet design standards for sign consistency as detailed in Sec. 18-716.
- Compliance with the large development signage plan is required as a condition of the approved sign permit.
- A sign plan is required whenever a large development signage plan is called for, and must be approved by the director.
- For special displays (that are not exempt/prohibited or otherwise compliant), approval from the Thornton Arts, Sciences and Humanities Council (TASHCO) is required via special review and application.
- Variance requests and appeals regarding sign permits, sign plans, or sign code adjustments are processed before the board as outlined in Section 18-718.

## Full detail

This page publishes an overview of every zoning district plus a sample of 3 districts in full. Complete zone-by-zone requirements for all 5 zoning districts in Thornton — every sign type, every field — are available with a free PermitPal account: https://app.permitpal.io/?address=Thornton+CO&override=true&utm_source=landing&utm_medium=city-page&utm_campaign=city-thornton

---

PermitPal — AI sign code research. Full HTML page: https://permitpal.io/sign-regulations/colorado/thornton