What city is 80503 in?

80503 is a Longmont, CO mailing address. By land area, 9% lies inside Longmont and 4% lies inside Niwot; the rest is outside any Census-defined city or community.

What is the population of 80503?

About 35,846 people (±1,374), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 35,863.

What is the median household income in 80503?

$113,620 (±$10,324), compared with $95,470 for Colorado as a whole. Half the households in the ZIP code earn more and half earn less.

How many carrier routes and mailboxes are in 80503?

26 USPS carrier routes with 15,573 residential and 369 business mailboxes (15,943 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.

What ZIP codes are near 80503?

The closest, measured center to center: 80544 (5 mi, Niwot), 80501 (5.7 mi, Longmont), 80301 (8.5 mi, Boulder), 80304 (9.5 mi, Boulder), 80504 (9.6 mi, Firestone) and 80513 (10.2 mi, Berthoud).

80503 ZIP Code, Longmont, CO

80503 is a ZIP code in Longmont, Colorado in Boulder County. It covers 92 square miles of land. The closest ZIP codes are 80544, 80501 and 80301. 35,846 people live here in 15,153 households. With about 391 people per square mile it is lightly settled, and owners and renters are mixed (66% own). Median household income is $113,620, above the Colorado median of $95,470.

Quick facts

Mailing city: Longmont, CO
County: Boulder County
Land area: 92 sq mi
Population: 35,846
Median household income: $113,620
Carrier routes: 26 (15,573 homes)

Key figures

Measure	Value
Residents	35,846
Households	15,153
Median household income	$113,620
Income per person	$64,526
Median age	44.8
Homeowners	66.1%
Median home value	$755,500
Median rent	$1,872
Bachelor's degree or higher	59.9%
Average commute (minutes)	23.1
Households with kids under 18	25.5%
Moved in the past year	18.1%
Below the poverty line	5.8%
Broadband internet	95.8%
Speak a non-English language at home	8.7%

Household income

% of households	Value
<$10K	2.7%
$10–15K	0.8%
$15–25K	4.1%
$25–35K	2.6%
$35–50K	8.7%
$50–75K	13.2%
$75–100K	12.5%
$100–150K	17.3%
$150–200K	12.3%
$200K+	25.8%

Age

% of all residents	Value
<10	7.6%
10–19	13.2%
20–24	5.5%
25–34	12.2%
35–44	12.0%
45–54	13.3%
55–64	15.7%
65–74	12.3%
75+	8.4%

Tenure

% of housing units	Value
Owned, with mortgage	42.4%
Owned outright	21.5%
Rented	32.4%
Vacant	3.7%

Type of building

% of housing units	Value
Detached house	66.0%
Townhome	5.9%
2–4 units	3.4%
5–19 units	16.1%
20+ units	8.2%
Mobile / other	0.3%

Businesses in 80503

767 business establishments with 7,488 employees (ZIP Codes Business Patterns 2023).

Professional, Scientific, and Technical Services: 195
Construction: 88
Health Care and Social Assistance: 81
Real Estate and Rental and Leasing: 68
Other Services (except Public Administration): 52
Administrative and Support and Waste Management and Remediation Services: 38
Retail Trade: 37
Finance and Insurance: 34

EDDM carrier routes

80503 has 26 USPS carrier routes with 15,573 residential and 369 business mailboxes. Open the EDDM route map.

Carrier routes in 80503

80503 has 26 USPS carrier routes (6 city (C), 20 rural (R)) with 15,573 residential and 369 business mailboxes. Routes range from 351 homes (R009) to 1,181 homes (R025); the median route has 562 homes. The Census counted 15,153 households in 80503 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.

Homes per route	Routes
1–249	0
250–499	10
500–749	11
750–999	4
1,000–1,499	1
1,500+	0

Best routes in 80503 for…

Most businesses

For B2B offers: office supplies, cleaning, IT, catering and commercial services.

Route C085 — USPS business mailboxes 75, 420 homes
Route R007 — USPS business mailboxes 43, 501 homes
Route R019 — USPS business mailboxes 36, 614 homes
Route C075 — USPS business mailboxes 36, 467 homes
Route R003 — USPS business mailboxes 25, 443 homes

Select these 5 routes on the route map

Every carrier route in 80503

Route	Type	Homes	Businesses	Est. median income	Est. owners	Est. families with kids	Est. moved in past year
C063	City	451	2	$150,353	—	—	—
C069	City	456	1	$100,945	—	—	—
C075	City	467	36	$109,808	—	—	—
C080	City	484	8	$89,064	—	—	—
C085	City	420	75	$192,465	—	—	—
C093	City	670	3	$89,064	—	—	—
R003	Rural	443	25	$155,199	—	—	—
R005	Rural	509	14	$200,001+	—	—	—
R007	Rural	501	43	$149,465	—	—	—
R008	Rural	672	3	$177,094	—	—	—
R009	Rural	351	2	$112,353	—	—	—
R012	Rural	762	16	$154,640	—	—	—
R014	Rural	434	3	$174,822	—	—	—
R016	Rural	644	1	$109,808	—	—	—
R017	Rural	459	16	$145,763	—	—	—
R018	Rural	784	1	$182,971	—	—	—
R019	Rural	614	36	$149,465	—	—	—
R022	Rural	512	18	$128,897	—	—	—
R024	Rural	708	24	$192,465	—	—	—
R025	Rural	1,181	14	$177,094	—	—	—
R028	Rural	612	0	$60,227	—	—	—
R031	Rural	817	0	$182,971	—	—	—
R036	Rural	785	8	$154,640	—	—	—
R039	Rural	681	7	$182,971	—	—	—
R048	Rural	659	2	$174,822	—	—	—
R053	Rural	497	11	$182,971	—	—	—

Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 80503 on the EDDM route map.

How route demographics are estimated

Mailbox counts come from USPS; demographics are estimates

The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).

How a route gets its figures: the block-group length-share method

We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.

Margins of error

Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.

Different years

USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.

Why some routes show identical figures

Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.

Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Nearby ZIP codes

80544 — Niwot CDP, CO (5 mi)
80501 — Longmont city, CO (5.7 mi)
80301 — Boulder city, CO (8.5 mi)
80304 — Boulder city, CO (9.5 mi)
80504 — Firestone town, CO (9.6 mi)
80513 — Berthoud town, CO (10.2 mi)
80540 — Allenspark CDP, CO (10.7 mi)
80455 — Glendale CDP, CO (11.1 mi)

Areas that include 80503

Where it ranks

No. 2 of 15: highest median age in Boulder County

Mail every home in 80503

Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.

EDDM guides

ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 80503, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.

Frequently asked questions

What city is 80503 in?: 80503 is a Longmont, CO mailing address. By land area, 9% lies inside Longmont and 4% lies inside Niwot; the rest is outside any Census-defined city or community.
What county is 80503 in?: 80503 is in Boulder County.
What is the population of 80503?: About 35,846 people (±1,374), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 35,863.
What is the median household income in 80503?: $113,620 (±$10,324), compared with $95,470 for Colorado as a whole. Half the households in the ZIP code earn more and half earn less.
How many carrier routes and mailboxes are in 80503?: 26 USPS carrier routes with 15,573 residential and 369 business mailboxes (15,943 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
What ZIP codes are near 80503?: The closest, measured center to center: 80544 (5 mi, Niwot), 80501 (5.7 mi, Longmont), 80301 (8.5 mi, Boulder), 80304 (9.5 mi, Boulder), 80504 (9.6 mi, Firestone) and 80513 (10.2 mi, Berthoud).

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.