Data center siting snapshot: Maricopa County, Arizona

Line miles are measured from the archived HIFLD Transmission Lines layer inside the Census county boundary. Mapped lines are not available capacity.

What the public record shows

The archived HIFLD map displays approximately 1877.7 miles of 230 kV-and-above transmission line within Maricopa County, including 555.4 miles at 500 kV or higher ^[1]. An additional 94.0 miles of 115–161 kV line are mapped in the area ^[2]. Arizona Public Service, Salt River Project, and Ameren Illinois hold the most mapped 115 kV+ line miles ^[3]. Thirty-one named line endpoints, typically substations or switchyards, touch these high-voltage lines ^[4]. Retail electric utilities with approximate service territories in the county include USBIA-San Carlos Project, Tohono O'odham Utility Authority, Gila River Indian Utility Authority, Electrical District No. 8 Maricopa, and Buckeye Water C&d District ^[5].

As of 2026-11-09, records show no county- or city-level data center moratorium or ordinance for Maricopa County ^[6]. Several state-level bills addressing data center siting and costs failed in 2026 ^{[7][8][9][10][11][12]}. HB2457 would have created a colocation pathway for generating facilities serving data centers ^[7]. HB2452 aimed to require county plans to designate land for data centers ^[8]. HB4009 sought to direct state mapping of suitable parcels ^[9]. HB2949 would have required large data centers to pay incremental energy costs ^[10]. SB1463 and SB1467 both proposed repealing data center tax relief ^[11][12].

Drafted by our local model from the numbered facts below, then checked sentence by sentence by a second model and a rules-based check.

Data center rules on record

Rule records come from The MW Desk legislation tracker, which includes rows from the Moratorium Nation dataset by Michael J. Bommarito (CC BY 4.0). Statuses change; confirm with the jurisdiction's own record.

Utilities on record

USBIA-San Carlos Project, Tohono O'odham Utility Authority, Gila River Indian Utility Authority (Gricua), Electrical District No. 8 Maricopa, Buckeye Water C&d District, Tonopah Irrigation District. (HIFLD/EIA-861 territory polygons; approximate and often overlapping.)

Market context on The MW Desk: Phoenix.

Sources

1. [1] The archived HIFLD map shows about 1877.7 miles of 230 kV-and-above transmission line inside Maricopa County, AZ: 555.4 miles at 500 kV or more, 223.8 miles at 345 kV and 1098.5 miles at 230 kV. Source: HIFLD Transmission Lines (archived by SeerAI, CC BY 4.0)
2. [2] The same map shows about 94.0 miles of 115–161 kV line in the county. Source: HIFLD Transmission Lines (archived by SeerAI, CC BY 4.0)
3. [3] Owners of record with the most mapped 115 kV+ line miles in the county: Arizona Public Service, Salt River Project, Ameren Illinois (AIC). Source: HIFLD Transmission Lines (archived by SeerAI, CC BY 4.0)
4. [4] 31 named line endpoints touching 230 kV+ lines (usually substations or switchyards) are mapped inside the county. Source: HIFLD Transmission Lines (archived by SeerAI, CC BY 4.0)
5. [5] Retail electric utilities whose mapped service territory covers part of the county include: USBIA-San Carlos Project, Tohono O'odham Utility Authority, Gila River Indian Utility Authority (Gricua), Electrical District No. 8 Maricopa, Buckeye Water C&d District. Territory boundaries are approximate. Source: HIFLD Electric Retail Service Territories (EIA-861 based; archived by SeerAI, CC BY 4.0)
6. [6] Our records hold no county- or city-level data center moratorium or ordinance for Maricopa County as of 2026-11-09. Source: The MW Desk legislation tracker
7. [7] Arizona state/utility level, Arizona: HB2457 (2026) (Would create a colocation pathway for electric generating facilities serving data centers and other large loads, reducing certificate requirements for qualifying adjacent generation). Status: failed, dated 2026-06-10. Source: HB 2457 (AZ 2026) - FastDemocracy bill tracker
8. [8] Arizona state/utility level, Arizona: HB2452 (2026) (Would require county comprehensive plans to designate enough land for data centers and small modular reactors so counties do not prevent effective siting). Status: failed, dated 2026-02-26. Source: HB 2452 (AZ 2026) - FastDemocracy bill tracker
9. [9] Arizona state/utility level, Arizona: HB4009 (2026) (Would direct State Land Department mapping of state parcels suitable for data center siting). Status: failed, dated 2026-02-26. Source: HB 4009 (AZ 2026) - FastDemocracy bill tracker
10. [10] Arizona state/utility level, Arizona: HB2949 (2026) (Would require large data centers with at least 100 MW peak demand to pay their own incremental energy costs and bar pass-through to other utility customers). Status: failed, dated 2026-02-05. Source: HB 2949 (AZ 2026) - FastDemocracy bill tracker
11. [11] Arizona state/utility level, Arizona: SB1463 (2026) (Would repeal data center tax relief and related exemptions). Status: failed, dated 2026-02-02. Source: SB 1463 (AZ 2026) - FastDemocracy bill tracker
12. [12] Arizona state/utility level, Arizona: SB1467 (2026) (Would repeal data center tax relief and related exemptions). Status: failed, dated 2026-02-02. Source: SB 1467 (AZ 2026) - FastDemocracy bill tracker