GILLIAM
SubstationLouisiana · SOUTHWESTERN ELECTRIC POWER CO
At a glance
GILLIAM is an electric transmission substation in Louisiana, on SOUTHWESTERN ELECTRIC POWER CO's transmission network. It is classified as unclassified and connects 1 transmission line. 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
Ownership
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #123101 | — | SOUTHWESTERN ELECTRIC POWER CO | IN SERVICE | 0.0 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of GILLIAM, 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 |
|---|---|---|---|---|---|---|---|
| LONGWOOD | Substation-Adjacent | LA | Caddo Parish | 345 kV | 600 MW | 4.3 yrs | 65.0 |
| EDWARDS STREET | Substation-Adjacent | LA | Caddo Parish | 138 kV | 100 MW | 4.3 yrs | 61.4 |
| ARSENAL HILL | Substation-Adjacent | LA | Caddo Parish | 138 kV | 100 MW | 4.3 yrs | 61.4 |
| FORT HUMBUG | Substation-Adjacent | LA | Caddo Parish | 138 kV | 100 MW | 4.3 yrs | 61.3 |
| MC WILLIE | Substation-Adjacent | LA | Caddo Parish | 138 kV | 100 MW | 4.3 yrs | 61.2 |
| EC Coal Harrison County | Greenfield | TX | Harrison County | — | — | 3.5 yrs | 60.7 |
| EC Near Lieberman | Greenfield | LA | Caddo | — | — | 4.3 yrs | 60.5 |
| OZ Cass | Greenfield | TX | Cass | — | — | 3.5 yrs | 60.4 |
Who owns the transmission lines at GILLIAM?
The 1 connected line listed above is owned by SOUTHWESTERN ELECTRIC POWER CO. Their combined recorded length is about 0 miles.
How do candidate sites near GILLIAM score?
The 8 highest-scoring candidate sites within about 25 miles range from 60 to 65 on the 0–100 DC Readiness scale. They fall in Caddo Parish, Harrison County, Caddo, Cass. The Louisiana average across 1,762 scored sites is 53.1. 615 of those Louisiana sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
How many transmission lines connect to GILLIAM substation?
1 transmission line terminate at or pass through GILLIAM in the HIFLD line data. Together the listed lines cover about 0 miles.
Who owns GILLIAM substation?
HIFLD does not publish substation owners directly. Most of the transmission lines that end at GILLIAM belong to SOUTHWESTERN ELECTRIC POWER CO. GridCensus derives this from the line data, so confirm ownership with the utility for anything contractual.
Where is GILLIAM substation located?
GILLIAM is in Louisiana at 32.8176, -93.8669. The datacenter candidate sites closest to it are in Caddo Parish, Harrison County, Caddo.
Are there datacenter candidate sites near GILLIAM substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of GILLIAM. The highest-scoring is LONGWOOD at 65/100. Across Louisiana, the average DC Readiness score is 53.1.
More in Louisiana
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, “GILLIAM substation, Louisiana”, https://gridcensus.com/substations/louisiana/gilliam-eee78663 (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 GILLIAM substation, Louisiana 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.