MADISON
SubstationIndiana · DUKE ENERGY INDIANA, LLC
At a glance
MADISON is an electric transmission substation in Indiana, on DUKE ENERGY INDIANA, LLC's transmission network. It is classified as sub-transmission (138 kv) and connects 7 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 |
|---|---|---|---|---|
| #101339 | 138 kV | DUKE ENERGY INDIANA, LLC | IN SERVICE | 82.2 mi |
| #106748 | 138 kV | DUKE ENERGY INDIANA, LLC | IN SERVICE | 3.3 mi |
| #107966 | 138 kV | — | IN SERVICE | 9.2 mi |
| #109860 | 138 kV | DUKE ENERGY INDIANA, LLC | IN SERVICE | 0.5 mi |
| #126913 | 138 kV | DUKE ENERGY INDIANA, LLC | IN SERVICE | 12.3 mi |
| #150316 | 138 kV | DUKE ENERGY INDIANA, LLC | IN SERVICE | 2.6 mi |
| #167166 | — | DUKE ENERGY INDIANA, LLC | IN SERVICE | 1.6 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of MADISON, 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 |
|---|---|---|---|---|---|---|---|
| NOBLESVILLE | Substation-Adjacent | IN | Hamilton County | 345 kV | 600 MW | 3.0 yrs | 67.7 |
| SUNNYSIDE | Substation-Adjacent | IN | Marion County | 345 kV | 600 MW | 3.0 yrs | 67.2 |
| GREENTOWN | Substation-Adjacent | IN | Howard County | 765 kV | 1,000 MW | 3.0 yrs | 66.0 |
| UNKNOWN124011 | Substation-Adjacent | IN | Hamilton County | 230 kV | 300 MW | 3.0 yrs | 65.5 |
| TAP138992 | Substation-Adjacent | IN | Hancock County | 230 kV | 300 MW | 3.0 yrs | 64.7 |
| FALL CREEK | Substation-Adjacent | IN | Henry County | 345 kV | 600 MW | 3.0 yrs | 64.5 |
| UNKNOWN124480 | Substation-Adjacent | IN | Hancock County | 230 kV | 300 MW | 3.0 yrs | 64.3 |
| OZ Marion | Greenfield | IN | Marion | — | — | 3.0 yrs | 63.6 |
How does MADISON compare with other substations in Indiana?
Indiana has 2,077 substation records in HIFLD, of which 306 carry a station name; the rest are unnamed tap points, risers and line ends. 114 named substations in the state are in MADISON's 115–229 kV band (37% of named stations). 84 sit in a higher band. 69 named substations in Indiana operate at 345 kV or above. The highest voltage recorded in the state is 765 kV, and the state median is 138 kV.
Who owns the transmission lines at MADISON?
The 7 connected lines listed above are owned by DUKE ENERGY INDIANA, LLC. Line voltages range from 138 kV to 138 kV. Their combined recorded length is about 111.7 miles.
How do candidate sites near MADISON score?
The 8 highest-scoring candidate sites within about 25 miles range from 64 to 68 on the 0–100 DC Readiness scale. They fall in Hamilton County, Marion County, Howard County, Hancock County. The Indiana average across 8,629 scored sites is 54. 1,024 of those Indiana sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
What voltage is MADISON substation?
MADISON has a maximum voltage of 138 kV. That places it in the 115–229 kV band. The median named US substation in this dataset is 115 kV, so MADISON is above the national midpoint.
How many transmission lines connect to MADISON substation?
7 transmission lines terminate at or pass through MADISON in the HIFLD line data. The connected lines listed here run at 138 kV. Together the listed lines cover about 111.7 miles.
Who owns MADISON substation?
HIFLD does not publish substation owners directly. Most of the transmission lines that end at MADISON belong to DUKE ENERGY INDIANA, LLC. GridCensus derives this from the line data, so confirm ownership with the utility for anything contractual.
Where is MADISON substation located?
MADISON is in Indiana at 40.0870, -85.6451. The datacenter candidate sites closest to it are in Hamilton County, Marion County, Howard County.
Are there datacenter candidate sites near MADISON substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of MADISON. The highest-scoring is NOBLESVILLE at 68/100. Across Indiana, the average DC Readiness score is 54.
Other 138 kV substations in Indiana
- NORTHEAST· 14 lines
- ROBISON PARK (138 KV)· 12 lines
- TWIN BRANCH (138 KV)· 12 lines
- LINCOLN· 10 lines
- BROWN (138 KV)· 8 lines
- MCKINLEY· 8 lines
- NEW CARLISLE· 8 lines
- SOUTH BEND· 8 lines
- All named substations in Indiana· 306 stations
- Datacenter candidate sites in Indiana· 8,629 sites
- Brownfield and retired plant sites in Indiana
- Substations by state
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, “MADISON substation, Indiana”, https://gridcensus.com/substations/indiana/madison-eeff07de (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 MADISON substation, Indiana 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.