Collin County's overcrowded jail could get a major expansion under an $820 million bond package that commissioners are considering for the November ballot.

County Administrator Yoon Kim presented the proposal at the July 14 Commissioners Court meeting. Kim said he initially considered a $1.2 billion package before trimming it to the $820 million figure. A jail expansion is the centerpiece, though the bond would also fund other county projects.

The county tried a similar approach in 2023, when commissioners called a bond election that included $261.8 million for court and detention facility projects as part of a $683 million package. Construction on a 90,000-square-foot intake and housing building and a 450-bed infirmary began in 2022, funded through earlier bonds and federal recovery funds. The new proposal dwarfs those figures.

Allen Police transport all arrestees to the Collin County Detention Facility in McKinney, the same jail that's over capacity. When that facility runs out of space, the county pays to house inmates elsewhere.

That's already happening at significant cost. The Sheriff's Office requested $504,994 at the July 13 Commissioners Court meeting to cover out-of-county inmate housing through September, according to Shelby Williams, a candidate for Collin County Commissioner. The court had already approved roughly $932,000 in April to cover the same costs through June. Combined, the county has spent or authorized more than $1.4 million in 2026 housing inmates in other counties' jails.

The detention facility operates at or above capacity most of the time, county officials said at the July 14 meeting.

The overcrowding tracks with rapid population growth. Collin County added nearly 43,000 residents between July 2024 and July 2025, the second-largest numeric increase among all U.S. counties, according to U.S. Census Bureau data reported by the Texas Tribune in March 2026.

No vote has been taken to place the $820 million bond on the November 2026 ballot.