HB 2257 mandates that all Texas county sheriffs apply for and participate in federal immigration enforcement programs, specifically those authorized under Section 287(g) of the Immigration and Nationality Act. The bill requires sheriffs to seek participation in one of two models: (1) the Jail Enforcement Model, which allows local officers to process detained noncitizens for removal, or (2) the Warrant Service Officer Model, which authorizes trained officers to serve federal administrative immigration warrants. Counties with populations over 250,000 must submit applications for participation by July 1, 2026, while smaller counties have staggered deadlines extending to July 1, 2028. The bill prohibits successive sheriffs from withdrawing from these agreements once entered into by their predecessors. Additionally, the Texas Attorney General is empowered to bring legal action against sheriffs who fail to comply with the law. The bill also establishes a financial assistance program administered by the Texas Comptroller, providing funding for salary offsets, training costs, and equipment required for participation in these federal programs. However, funding is capped at supporting no more than 25 officers per year per county.