County · code 08013
Boulder CountyColorado
Boulder County is a county in Colorado with its seat in Boulder, formed in 1861.
- Founded1861
- County seatBoulder
- Named forBoulder Creek, Colorado and Boulder, Colorado
- Land area726 sq mi + 14 sq mi water
- Population330,758 2020 Census
- Parcels mapped131,686 checked 14 October 2026
Where it is
Boulder on the map of Colorado
Colorado has 64 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Founded in 1861
An old deed may name a county that no longer exists, or a boundary that has since moved.
Boulder County was created by Colorado Territory in 1861. The county was named after Boulder Creek and the city of Boulder. In 2001, Boulder County lost territory to the creation of Broomfield County.
- 1861Boulder County created Boulder created by Colorado Territory from non-county area. · Colo. Terr. Laws 1861, 1st sess., sec. 22/p. 55
- 2001Lost territory Boulder lost to creation of Broomfield. · Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274
Land and parcels
What the maps cover in Boulder
Who publishes each layer, how good it is, and when we last checked.
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Parcels Good enough
Lot lines and tax-map numbers for 131,686 parcels from Boulder County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 14 October 2026 -
Address points Missing
No public address points layer found for Boulder County yet.
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Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Boulder by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
County government
- County government
The official website of Boulder County.
See your own lot on these maps
Open Boulder County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Boulder County
- When was Boulder County founded?
- Boulder County was founded in 1861, and named after Boulder Creek, Colorado and Boulder, Colorado.
- What is the county seat of Boulder County?
- The county seat of Boulder County is Boulder.
- Is there an online parcel map for Boulder County?
- Yes. Boulder County publishes a parcel map of 131,686 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Boulder County's boundary or name changed?
- Boulder County was created in 1861. Since then the Atlas of Historical County Boundaries records 1 later change, chiefly involving Broomfield County.
- Who issues building permits in Boulder County?
- The county's page on building permits: Licenses, Permits & Records. Inside a city or town, ask that city first.
- Is my lot in a flood zone?
- We do not have flood maps for Boulder County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby