MARION S
SubstationIllinois · AMEREN ILLINOIS COMPANY
MARION S is an electric transmission substation in Illinois, operated by AMEREN ILLINOIS COMPANY. It is classified as sub-transmission (138 kv) and connects 4 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 |
|---|---|---|---|---|
| #44538 | 161 kV | AMEREN ILLINOIS COMPANY | IN SERVICE | 2.8 mi |
| #45724 | 161 kV | AMEREN ILLINOIS COMPANY | IN SERVICE | 32.5 mi |
| #385 | 138 kV | AMEREN ILLINOIS COMPANY | IN SERVICE | 3.6 mi |
| #48173 | 138 kV | AMEREN ILLINOIS COMPANY | IN SERVICE | 9.2 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of MARION S, 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 |
|---|---|---|---|---|---|---|---|
| SHAWNEE | Substation-Adjacent | IL | Massac County | 500 kV | 1,000 MW | 4.6 yrs | 81.3 |
| JOPPA 345 | Substation-Adjacent | IL | Massac County | 345 kV | 600 MW | 4.6 yrs | 75.6 |
| JOPPA | Substation-Adjacent | IL | Johnson County | 230 kV | 300 MW | 4.6 yrs | 70.7 |
| UNKNOWN121869 | Substation-Adjacent | IL | Massac County | 161 kV | 100 MW | 4.6 yrs | 70.4 |
| Greenfield (SHAWNEE - WEST FRANKFORT EAST) | Greenfield | IL | Massac County | 345 kV | 600 MW | 4.6 yrs | 69.1 |
| WEST FRANKFORT | Substation-Adjacent | IL | Williamson County | 230 kV | 300 MW | 4.6 yrs | 69.1 |
| Greenfield (SHAWNEE - WEST FRANKFORT EAST) | Greenfield | IL | Massac County | 345 kV | 600 MW | 4.6 yrs | 69.0 |
| Greenfield (SHAWNEE - WEST FRANKFORT EAST) | Greenfield | IL | Johnson County | 345 kV | 600 MW | 4.6 yrs | 67.3 |
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
This page shows a public slice of the GridCensus dataset for MARION S substation, Illinois. Pro and Enterprise plans unlock the full 164,098-site catalog, raw sub-scores, parcel ownership, interconnection-queue detail, saved searches, and programmatic API access.