Reviewed and updated October 9, 2026 by the SearchSystems.net editorial team. The arrest counts are the ones each agency reported to the FBI, as the FBI held them on October 8, 2026. The jail figures are from the Vera Institute of Justice's Incarceration Trends data. Every office link was opened and checked against the office's own site on September 23, 2026.
Boulder County, Colorado, has about 330,000 residents (2024 Census Bureau estimate), and arrests there are reported to the FBI by the Boulder County Sheriff's Office, four city agencies and two campus, state or other agencies. An arrest leaves the same records whoever makes it: the arresting agency's report, the record of anyone held at the county jail, and, if the District Attorney files charges, a case in the Boulder County District Court. This guide says who keeps each one, what it costs and who may see it, with the arrest counts each agency reported.
This guide covers who makes arrests, how many arrests, booking and the jail, finding an arrest, copies, cities and common questions.
Related guides: Boulder County public records, Colorado arrest records, Colorado inmate search and Colorado criminal records.
Who Makes Arrests in Boulder County
The Boulder County Sheriff's Office is the county agency that reports arrests to the FBI for Boulder County. It reported 1,242 arrests for 2025.
Arrests inside four of the county's cities are reported to the FBI by an agency of the city's own, listed here with the Census population and what each reported:
- Boulder, 106,803 residents: 3,201 arrests reported for 2025.
- Longmont, 99,818 residents: 2,378 arrests reported for 2025.
- Lafayette, 30,587 residents: 635 arrests reported for 2025.
- Louisville, 20,811 residents: 309 arrests reported for 2025.
A city on that list is reported separately whether the officers are the city's own or the sheriff's under contract; the FBI's list does not say which.
The Erie Police Department is listed by the FBI across two counties including Boulder County, so its arrests are not broken out for Boulder County here.
The FBI's agency list also places these agencies in Boulder County: Colorado Department of Revenue in Marijuana Enforcement Criminal Investigation, Boulder County (state agency); the University of Colorado at Boulder (campus police).
How Many Arrests Each Agency Reports in Boulder County
Each agency reports its arrests to the FBI by month, and the FBI publishes them on the Crime Data Explorer. These are the full-year totals, all offenses, as the FBI held them on October 8, 2026; a year with months missing or not reported is left out.
- Boulder: 3,201 for 2025, 3,103 for 2024, 2,989 for 2023, 3,133 for 2021, 3,236 for 2020 and 4,434 for 2019; 2022 is missing months.
- Longmont: 2,378 for 2025, 3,073 for 2024, 2,761 for 2023, 2,589 for 2022, 2,404 for 2021 and 2,268 for 2020.
- Boulder County Sheriff's Office: 1,242 for 2025, 774 for 2024, 841 for 2023, 736 for 2022, 1,677 for 2021 and 1,729 for 2020.
- Lafayette: 635 for 2025, 848 for 2024, 732 for 2023, 541 for 2022, 586 for 2021 and 570 for 2020.
- Louisville: 309 for 2025, 342 for 2024, 350 for 2023, 321 for 2022, 356 for 2021 and 342 for 2020.
Together, the five agencies with all twelve months of 2025 on file reported 7,765 arrests that year. The four of them with both 2025 and 2024 complete reported 6,523 in 2025 against 7,366 in 2024, down 11 percent.
Through August 2026, the five agencies with every month so far on file reported 4,507 arrests, against 5,366 in the same months of 2025.
Booking: Where People Arrested in Boulder County Are Held
The county jail is where a person arrested in Boulder County and kept in custody ends up, whichever agency made the arrest, though a city department may hold someone in its own cells first and a person cited and released at the scene is never booked. The jail's record of each person held, with the charges, is a public record of the arrest, and once the person is released or sentenced the record continues in the court file.
On an average day in 2025 the jail held about 320 people, down from about 410 in 2019. Its rated capacity in 2025 was 543 beds, and it ran at 59 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
SearchSystems opened and checked the custody page of the Boulder County Sheriff's Office at bouldercounty.gov/safety/jail/listing-and-booking-reports (page title: Daily Booking and Listing Reports | Boulder County), phone 303-441-3600, 5600 Flatiron Parkway Boulder, CO 80301, Monday - Friday 8 a.m. - 5 p.m., which answered when SearchSystems opened it on September 23, 2026.
That page is the place to look for someone who was booked recently; a person cited and released at the scene, or held only a few hours by a city department, will not be on it.
A person sentenced to prison serves the sentence in a facility of the Colorado Department of Corrections, whose inmate locator is at cdoc.colorado.gov.
How to Find Out About an Arrest in Boulder County
An arrest in Boulder County can be traced in three places, depending on where the case stands: the custody page of the Boulder County Sheriff's Office described above, for anyone booked into the county jail; the case index of the Boulder County District Court, which shows whether charges were filed and the next court date (the court records page SearchSystems verified is at coloradojudicial.gov/courts/trial-courts/boulder-county, phone (303)441-3750); the District Attorney, which decides whether an arrest becomes a charge (its page is at bouldercounty.gov/district-attorney, phone 303-441-3700).
Colorado is one of the states that lets anyone look up another person's statewide criminal history: the state runs an online name-based criminal history check open to the public, through the Colorado Bureau of Investigation. That record shows what agencies reported to the state, which is wider than one county's court index but can lag it.
Getting a Copy of an Arrest Record in Boulder County
The report of an arrest is released by the agency that made it; the jail and the court hold their own records of the same event, but not the report. Under the Colorado Open Records Act the agency must answer within 3 working days, extendable to 7 when there are extenuating circumstances, and it may charge research and retrieval time after the first hour, plus copying.
- An arrest by the Boulder County Sheriff's Office: ask its records unit, reached through the office at 303-441-3600.
- An arrest in Boulder, Longmont, Lafayette or Louisville: the records unit of the agency that reports for that city; the city guides linked above name each city's records office.
- An arrest by Colorado Department of Revenue in Marijuana Enforcement Criminal Investigation, Boulder County or the University of Colorado at Boulder: the records office of the agency involved.
- A defendant who has been charged gets the report through the case: the District Attorney, 303-441-3700, handles discovery for pending cases.
- The court file of a case that was filed: the Boulder County District Court, through the court records page at coloradojudicial.gov, phone (303)441-3750.
- Any county record that is not posted: the county records request page SearchSystems verified is at bouldercountyco.govqa.us (page title: BOULDER COUNTY COLORADO PUBLIC RECORDS REQUEST CENTER).
- Your own statewide record: a name-based or fingerprint-based request to the Colorado Bureau of Investigation.
Cities in Boulder County: Who Reports the Arrests
The FBI lists a separate arrest reporting agency for four of the nine cities in Boulder County: Boulder, Longmont, Lafayette and Louisville. Superior, Lyons, Nederland, Jamestown and Ward have no separate reporting agency in the FBI's list.
Wherever in the county the arrest happens, a person kept in custody goes to the county jail and the case goes to the Boulder County District Court.
SearchSystems has a guide to the offices of these cities in Boulder County, with the 2024 Census Bureau population; a city with its own arrest records guide opens there:
Frequently Asked Questions
How many arrests are made in Boulder County each year?
Boulder reported 3,201 arrests to the FBI for 2025, and the five agencies with every month of 2025 on file reported 7,765 between them.
How do I find out if someone is in jail in Boulder County?
Look on the custody page of the Boulder County Sheriff's Office at bouldercounty.gov, or call 303-441-3600. It covers people booked into the county jail.
Where are people arrested in Boulder County booked?
Those kept in custody go to the county jail, run by the Boulder County Sheriff's Office; a person cited and released at the scene is not booked.
Are arrest records public in Boulder County?
The court files of criminal cases are public, and so is the statewide criminal history kept by the Colorado Bureau of Investigation: the state runs an online name-based criminal history check open to the public. The arrest report itself is released by the agency that made the arrest, under the Colorado Open Records Act.
How do I get a copy of an arrest report in Boulder County?
From the agency that made the arrest: the Boulder County Sheriff's Office for its own arrests, or the agency that reports for the city where it happened. Under the Colorado Open Records Act the answer is due within 3 working days, extendable to 7 when there are extenuating circumstances; the county records request page SearchSystems verified is at bouldercountyco.govqa.us.
Is this the official Boulder County website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official county, court and state offices described above and does not hold records, charge for them or take requests.