SB 658 mandates that sheriffs in counties with populations of 250,000 or more enter into agreements with U.S. Immigration and Customs Enforcement (ICE) under Section 287(g) of the Immigration and Nationality Act or similar programs to enforce federal immigration laws. It also allows smaller counties to participate voluntarily. The bill establishes a grant program to reimburse smaller counties for costs associated with these agreements and outlines accountability measures, including reporting and enforcement mechanisms. Sheriffs must report activities and attempts to enter into agreements annually, and the attorney general is authorized to enforce compliance.