Which ZIP code in Boulder County has the lowest median age?

80310 (Boulder), at 19.3 (±0.2), among 15 ZIP codes with at least 1,000 residents.

Why are some ZIP codes missing?

ZIP codes with fewer than 1,000 residents are left out because their survey estimates swing too much to rank, and so are ZIP codes where the Census Bureau did not publish this figure.

Youngest ZIP codes in Boulder County, CO

These are the 15 ZIP codes in Boulder County with the lowest median age, out of 15 with at least 1,000 residents. 80310 (Boulder, 19.3), 80302 (Boulder, 24.9) and 80303 (Boulder, 29.3) lead the list. There is no single "best" ZIP code in Boulder County; the right one depends on who you want to reach, so the same ZIP codes are ranked several ways below.

Youngest ZIP codes in Boulder County

Rank	ZIP	Mailing city	Median age	Residents	Households	Residential mailboxes
1	80310	Boulder	19.3 ±0.2	7,692	2	—
2	80302	Boulder	24.9 ±1.5	29,569	12,425	12,329
3	80303	Boulder	29.3 ±1.2	24,996	11,783	12,581
4	80305	Boulder	36.7 ±2.1	16,291	6,976	7,285
5	80301	Boulder	36.9 ±1.7	25,007	12,371	13,814
6	80020	Broomfield	37.7 ±0.6	54,201	21,326	22,532
7	80516	Erie	37.7 ±0.8	39,048	13,616	14,966
8	80501	Longmont	38.4 ±1.8	44,147	18,945	19,651
9	80504	Longmont	39.5 ±0.9	63,451	24,077	25,785
10	80026	Lafayette	40.0 ±1.8	32,701	13,524	15,023
11	80027	Louisville	40.3 ±2.2	34,127	13,180	14,806
12	80304	Boulder	42.8 ±2.2	25,383	11,358	12,139
13	80466	Nederland	43.6 ±5.4	3,599	1,670	710
14	80503	Longmont	44.8 ±1.4	35,846	15,153	15,573
15	80540	Lyons	48.1 ±2.8	4,642	2,025	1,402

How we ranked them

Ranked by median age of all residents, lowest first (ACS 5-year estimates, 2020–2024). ZIP codes need at least 1,000 residents to be ranked; 15 of 21 qualify.

Which of these to mail, and why

Younger ZIP codes skew toward renters, students and young families: fitness, quick-service food, apartments, entertainment and first-time-buyer offers.

The top five ZIP codes on this list hold 43,557 households. Open any of them on the route map to see each carrier route's own figures before you choose.

Open 80310 on the EDDM route map

More rankings

Businesses that mail these ZIP codes

Map it and price it

EDDM guides

Frequently asked questions

Which ZIP code in Boulder County has the lowest median age?: 80310 (Boulder), at 19.3 (±0.2), among 15 ZIP codes with at least 1,000 residents.
How is this ranking calculated?: Ranked by median age of all residents, lowest first (ACS 5-year estimates, 2020–2024).
Why are some ZIP codes missing?: ZIP codes with fewer than 1,000 residents are left out because their survey estimates swing too much to rank, and so are ZIP codes where the Census Bureau did not publish this figure.

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