# NORTHWESTERN CORPORATION — Big Horn County, MT

**Citation:** NPMS FIPS 30003 / OPID 31632  
**Type / status:** inspection / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 2026-07-16

39.871587 active Natural Gas pipeline miles in Big Horn County, MT; public NPMS snapshot 2026-07-16.

## Document text

NORTHWESTERN CORPORATION (PHMSA OPID 31632) reported 39.871587 active Natural Gas pipeline miles in Big Horn County, MT (county FIPS 30003) in the public NPMS summary snapshot dated 2026-07-16. The snapshot includes active assets only and excludes permanently abandoned assets. Exact pipeline locations and restricted NPMS GIS data are not included.

## Provenance

- Official: Yes
- Source: <https://www.npms.phmsa.dot.gov/Documents/NPMS_Active_Pipe_County_Mileage.xlsx>
- Source ID: `npms-public-summaries`
- SHA-256: `b33230afa3fd031f99068446e2f5eadf555b0c0a928c5201e7f44cd42d292628`
- Retrieved: 2026-08-20T04:38:11.081Z
- Exported: 2026-08-24T16:21:34.749Z
- Document slug: `npms-mileage-c5f6b2d2502a9e05f166491d`

### Source metadata

```json
{
  "materialSubtype": "pipeline_mileage",
  "dataAsOf": "2026-07-16",
  "dateBasis": "data_as_of_not_publication_date",
  "fips": "30003",
  "stateFips": "30",
  "state": "MT",
  "county": "Big Horn County",
  "region": "Big Horn County, MT",
  "operator": {
    "id": "31632",
    "name": "NORTHWESTERN CORPORATION"
  },
  "commodity": "Natural Gas",
  "mileage": 39.87158712,
  "plantCount": null,
  "snapshotScope": "active_assets_only",
  "personalContactDataExcluded": true,
  "restrictedGisExcluded": true,
  "provenance": {
    "workbook": "pipeline_mileage",
    "sheet": "Summary - Cnty, Oper, Commodity",
    "rowNumber": 7054,
    "rowSha256": "ceb79fcc898be65c1bc628090cc711ad83566ed69e077f92f882685781d219bd"
  },
  "citedSections": [
    "191.29"
  ],
  "caveat": "Public aggregate snapshot only. It is not a complete representation of exact pipeline locations, may be updated, and is not an agency finding about facility condition.",
  "jurisdiction": "US",
  "operatorName": "NORTHWESTERN CORPORATION"
}
```