AZ SB1100

Redefines Maricopa County boundaries by significantly reducing its geographic area, moving western and northern portions to other counties, effective December 31, 2025.

Creates new boundary descriptions for Gila County, Pinal County, Yavapai County, Yuma County, and La Paz County to accommodate territory removed from Maricopa County.

Establishes new Maricopa County boundaries using references to city limits (Phoenix, Scottsdale, Tempe, Mesa, Glendale, Litchfield Park, Avondale) and Interstate 10 as primary boundary markers instead of previous survey lines and geographic features.

Requires Legislative Council staff to prepare conforming legislation to update other sections of Arizona Revised Statutes consistent with these county boundary changes for consideration in the 2026 legislative session.