HORSE MESA DAM
SubstationArizona · SALT RIVER PROJECT
At a glance
HORSE MESA DAM is an electric transmission substation in Arizona, on SALT RIVER PROJECT's transmission network. It is classified as sub-transmission (115 kv) and connects 3 transmission lines. Substation proximity is one of the strongest speed-to-power signals for siting a datacenter — interconnection distance to an energized, high-voltage bus is often the binding constraint on time-to-energization.
Voltage & classification
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #308152 | 115 kV | SALT RIVER PROJECT | IN SERVICE | 21.0 mi |
| #310471 | 115 kV | SALT RIVER PROJECT | IN SERVICE | 17.6 mi |
| #311011 | 115 kV | SALT RIVER PROJECT | IN SERVICE | 11.7 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of HORSE MESA DAM, ranked by DC Readiness. Sites this close to an energized substation carry a strong speed-to-power advantage.
| Site | Type | State | County | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|---|---|
| BROWNING | Substation-Adjacent | AZ | Pinal County | 500 kV | 1,000 MW | 3.5 yrs | 65.7 |
| Williams Air Force Base | Brownfield | AZ | Maricopa | 69 kV | 2 MW | 3.5 yrs | 62.4 |
| EC Pinal Coal Area | Greenfield | AZ | Pinal | — | — | 3.5 yrs | 60.7 |
| THUNDERSTONE | Substation-Adjacent | AZ | Pinal County | 230 kV | 300 MW | 3.5 yrs | 60.3 |
| DINOSAUR | Substation-Adjacent | AZ | Pinal County | 230 kV | 300 MW | 3.5 yrs | 59.9 |
| GOLDFIELD | Substation-Adjacent | AZ | Pinal County | 230 kV | 300 MW | 3.5 yrs | 59.3 |
| EC Pinal Coal Area | Greenfield | AZ | Pinal | — | — | 3.5 yrs | 59.2 |
| SILVER KING | Substation-Adjacent | AZ | Gila County | 500 kV | 1,000 MW | 3.5 yrs | 58.9 |
How does HORSE MESA DAM compare with other substations in Arizona?
Arizona has 892 substation records in HIFLD, of which 466 carry a station name; the rest are unnamed tap points, risers and line ends. 87 named substations in the state are in HORSE MESA DAM's 115–229 kV band (19% of named stations). 138 sit in a higher band. 47 named substations in Arizona operate at 345 kV or above. The highest voltage recorded in the state is 500 kV, and the state median is 69 kV.
Who owns the transmission lines at HORSE MESA DAM?
The 3 connected lines listed above are owned by SALT RIVER PROJECT. Line voltages range from 115 kV to 115 kV. Their combined recorded length is about 50.3 miles.
How do candidate sites near HORSE MESA DAM score?
The 8 highest-scoring candidate sites within about 25 miles range from 59 to 66 on the 0–100 DC Readiness scale. They fall in Pinal County, Maricopa, Pinal, Gila County. The Arizona average across 3,816 scored sites is 48.5. 614 of those Arizona sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
What voltage is HORSE MESA DAM substation?
HORSE MESA DAM has a maximum voltage of 115 kV. That places it in the 115–229 kV band. The median named US substation in this dataset is 115 kV, so HORSE MESA DAM is at the national midpoint.
How many transmission lines connect to HORSE MESA DAM substation?
3 transmission lines terminate at or pass through HORSE MESA DAM in the HIFLD line data. The connected lines listed here run at 115 kV. Together the listed lines cover about 50.3 miles.
Who owns HORSE MESA DAM substation?
HIFLD does not publish substation owners directly. Most of the transmission lines that end at HORSE MESA DAM belong to SALT RIVER PROJECT. GridCensus derives this from the line data, so confirm ownership with the utility for anything contractual.
Where is HORSE MESA DAM substation located?
HORSE MESA DAM is in Arizona at 33.5907, -111.3439. The datacenter candidate sites closest to it are in Pinal County, Maricopa, Pinal.
Are there datacenter candidate sites near HORSE MESA DAM substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of HORSE MESA DAM. The highest-scoring is BROWNING at 66/100. Across Arizona, the average DC Readiness score is 48.5.
Other 115 kV substations in Arizona
About this data
Source: HIFLD Electric Substations and Transmission Lines (U.S. Department of Homeland Security), as published June 29, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “HORSE MESA DAM substation, Arizona”, https://gridcensus.com/substations/arizona/horse-mesa-dam-f5b6fadc (data as of June 29, 2026).
Dataset updated . Screening estimates derived from public data sources.
Substation attributes are derived from public HIFLD / EIA infrastructure data and may lag real-world upgrades or retirements. Voltage and connected-line counts are screening figures — confirm available capacity and interconnection terms directly with the operating utility and ISO.
Go deeper than the public screen
Every site and score for HORSE MESA DAM substation, Arizona is free to browse. Pro adds Watchtower on 25 sites, alerts when new candidate sites, datacenters or interconnection-queue requests appear in your markets, score and capacity history, and CSV export. Enterprise adds team seats, weekly data files for all 147,272 sites, the REST API and an MCP server for AI tools.