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 between September 23, 2026 and September 25, 2026.
Thornton, Colorado, in Adams County, has about 147,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Thornton is held at the county jail, run by the Adams County Sheriff's Office, and the jail's record of each person held is a public record. This guide says where to look for someone in custody, what the jail holds and who books people into it.
This guide covers the search, the jail, who books people, state prison and common questions.
Related guides: Thornton public records, Adams County inmate search, Thornton arrest records, Thornton warrants, Thornton criminal records, Thornton court records, Colorado arrest records and Colorado inmate search.
Finding Someone in Custody in Thornton
The county jail, run by the Adams County Sheriff's Office, holds everyone kept in custody after an arrest in Thornton, from every agency.
SearchSystems opened and checked the custody page of the Adams County Sheriff's Office at adamssheriffco.gov/community/public-records/inmate-search (page title: Inmate Search | Adams County Sheriff Office), phone (303) 288-1535, Monday - Friday, 8:00am - 5:00pm., which answered when SearchSystems opened it on September 23, 2026.
That page is the place to look for someone 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.
The Adams County Jail by the Numbers
On an average day in 2025 the jail held about 780 people, down from about 990 in 2019. Its rated capacity in 2025 was 1,197 beds, and it ran at 65 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Adams County has about 543,000 residents (2024 Census Bureau estimate), so the jail holds about 14 people for every 10,000 residents.
Who Books People Into the Adams County Jail
The Adams County Sheriff's Office and the agency that reports for Thornton (filed by the FBI as Thornton Police Department) make the arrests that end in a booking in and around Thornton.
The FBI's agency list also places one more agency in Adams County: the University of Colorado at Denver (campus police).
The Arvada Police Department and the Aurora Police Department are each listed by the FBI across several counties including Adams County, so their arrests are not broken out for Adams County here.
The largest arrest counts reported to the FBI were the Adams County Sheriff's Office's 6,472 for 2025, Thornton's 5,705 for 2025 and Westminster's 3,289 for 2025.
Together, the seven agencies in Adams County with all twelve months of 2025 on file reported 21,118 arrests to the FBI that year. Those kept in custody were booked into the county jail; a person cited and released at the scene was not.
The counts, agency by agency and year by year, are in Thornton arrest records.
From the Jail to State Prison
The jail holds people awaiting trial and people serving short sentences. A person sentenced to prison in Adams County serves the sentence in a facility of the Colorado Department of Corrections, whose inmate locator is at cdoc.colorado.gov.
Frequently Asked Questions
How do I find an inmate in Thornton?
Look on the custody page of the Adams County Sheriff's Office at adamssheriffco.gov, or call (303) 288-1535. It covers people booked into the county jail.
How many people are in the Adams County jail?
About 780 on an average day in 2025, the latest year in the Vera Institute's jail data, against a rated capacity of 1,197 beds.
What is the phone number for the Adams County jail?
(303) 288-1535, the number on the page of the Adams County Sheriff's Office SearchSystems verified.
Where do people sentenced to prison in Adams County go?
To a facility of the Colorado Department of Corrections; its inmate locator is at cdoc.colorado.gov.
Is this the official Thornton website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official city, county, court and state offices described above and does not hold records, charge for them or take requests.