Longmont, CO: Population, ZIP Codes & Nearby Cities

Longmont is an incorporated city in Boulder County, Colorado. In the dataset behind this page it has an estimated population of 102,474, sits at 40.169°N, 105.100°W, and observes Mountain time. Below you will find how it ranks inside Colorado, which ZIP codes it uses, the closest places around it, and how far it is from major US cities.

What are the key facts about Longmont, CO?

What is the population of Longmont, CO?

Longmont has an estimated population of 102,474. That makes it the 15th largest of the 448 places we list in Colorado, and the 2nd largest of 30 places in Boulder County. The typical place in Colorado has about 914 residents, so Longmont is many dozens of times larger than a typical place in the state.

Estimates for places of this size carry wider margins of error than those for big cities, so treat the figure as a guide to scale. Our guide to understanding city population numbers explains why sources disagree.

Places in Colorado with a similar population include Arvada (121,272), Westminster (113,166), Centennial (110,937), Highlands Ranch (105,631), Lafayette (99,645). Comparing these pages is a quick way to see how Longmont differs from communities of the same scale.

How dense is Longmont?

Longmont has about 3,383 people per square mile (1,306 per square kilometer), which we classify as suburban. Within Colorado, it is denser than about 93% of the listed places. Land at this level is usually a mix of single-family neighborhoods, shopping corridors and parks, where driving is common but destinations are close. Read how to interpret population density to see how we draw these lines.

What ZIP codes does Longmont use?

Longmont uses 3 ZIP codes: 80501, 80503, 80504. Several codes in one place usually reflect separate delivery areas, post offices or large buildings with their own code. Codes beginning with 8 are assigned to the Mountain West (Arizona, Colorado, Idaho, Nevada, New Mexico, Utah and Wyoming). Learn more in our guide to how ZIP codes work or check any code with the ZIP code lookup.

What time zone is Longmont in?

Longmont is in the Mountain time zone, which is UTC−7 from Coordinated Universal Time in standard time (IANA zone America/Denver). The area observes daylight saving time, so clocks move forward in March and back in November. The nearest listed place in a different time zone is Colby, KS, about 222 miles away, which gives a sense of how far the nearest zone boundary may be. Current local time: see the Mountain time hub. For the rules behind these zones, read US time zones explained.

Where is Longmont located in Colorado?

Longmont lies in the northern part of Colorado, at 40.169° north latitude and 105.100° west longitude. The state capital, Denver, is about 31 miles to the southeast. The closest listed place in another state is Cheyenne, WY, roughly 69 miles to the north, which shows how near Longmont is to a state line. For big-city services, the nearest place with more than 100,000 people is Boulder, CO, 13 miles to the southwest.

Which cities are near Longmont, CO?

The closest listed place to Longmont is Firestone, CO, 8.0 miles to the east. Of the eight nearest places below, 4 are in the same county. Distances are straight-line (great-circle) miles measured between place centers; see how distance is calculated.

Which county is Longmont in?

Longmont is in Boulder County, which has the Federal Information Processing Standards (FIPS) code 08013. The county contains 30 places in our data, 7 of which have their own page here and 23 smaller communities that appear only in county and state lists. Other places in the county include Boulder (124,345), Lafayette (99,645), Erie (27,003), Louisville (20,816), Superior (13,087). Codes like this one help separate places that share a name; see the guide to counties and FIPS codes.

How far is Longmont from major US cities?

Among six major hubs, Longmont is closest to Denver, CO at about 31 miles and farthest from New York, NY at about 1,631 miles in a straight line. Road distances are usually 10 to 30 percent longer. Try the distance calculator for any other pair.

Are there other places called Longmont?

No. In our data, Longmont in Boulder County, Colorado is the only place with this name, so the name alone is enough to identify it, though adding the state is still good practice in addresses and forms.

Planning a move to Longmont?

If you are weighing Longmont, start with the practical numbers: how far it is from where you live, whether it changes your time zone, and how its size and density compare with your current city. Use the distance calculator to measure the trip from where you live. The radius search tool lists every place within any distance of it. Our checklist for comparing cities explains what to check next.

Where to go next

Population and density come from a compiled dataset and are estimates. They may differ from official Census Bureau counts. Verify important figures at census.gov.