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The Mammoth handbook

Living in Mammoth, MT: what to set up and who to call

Mammoth has no town government of its own, so Madison County runs its elections and most services, and its children attend Harrison K-12 Schools. For an emergency, Ruby Valley Medical Center is the closest ER, 17.1 miles away.

Which school will my kid attend?How do I register to vote?ZIP codes
Mammoth has no town government. It’s a census-designated place in Madison County, so the county and regional agencies provide most services. This page answers what we can; the same answers appear on Mammoth’s town page under “Getting set up”.

I’m new in town

What to set up in Mammoth, and who provides it. Tap an answer for the details and where they come from.

PowerNorthWestern Energyinvestor-owned utility · 14.4¢/kWhMore →
InternetWhich providers serve MammothData pending · FCC map (D4)
Trash & dumpNot on file yetWe don’t have Mammoth’s trash rules yetMore →SchoolHarrison K-12 SchoolsWhich school depends on grade and addressMore →Register to voteIn personRules from vote.govMore →ZIP code59721Where people live, not P.O. boxesMore →
Home services

Power, water and internet

Who to call to start service at a new address in Mammoth.

Electricity

Power comes from NorthWestern Energy

NorthWestern Energy (NorthWestern Energy LLC - (MT)), an investor-owned utility, serves all of Mammoth. Its homes paid an average of 14.4¢ per kWh in 2025, about $102 a month (its average across Montana, for customers on its standard service). Montana lets you buy power from another supplier; 0% of NorthWestern Energy’s home customers do, and NorthWestern Energy still delivers it.

Start or move service: northwesternenergy.com · (888) 467-2669

Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.

Internet

Which providers serve Mammoth

Data pending · D4

This card will list the home internet providers the FCC’s National Broadband Map shows in Mammoth, the share of addresses that can get 100/20 Mbps and the share with fiber, with the map’s “as of” date.

Source to come: FCC Broadband Data Collection.

Trash & recycling

We don’t have Mammoth’s trash rules yet

Pickup rules, the dump and recycling in Mammoth.

Trash, recycling and bulk pickupNot on fileMammoth has no town government of its own, so look for trash and recycling rules on the county’s site.
Schools

Where your child goes to school

Public school districts and the school path by grade.

Mammoth kids go to
PK–5Harrison Schoolin Harrison
6–8Harrison 6-8in Harrison
9–12Harrison High Schoolin Harrison

Mammoth is in Harrison K-12 Schools.

Test scores and every school: see Schools →

U.S. Department of Education, NCES Common Core of Data, 2024–25. Enrollment rules and registration are the district’s.

Government & voting

No town hall: the county runs things

Mammoth is unincorporated, so Madison County is the local government.

Local governmentMadison CountyMammoth is a census-designated place: no town hall of its ownCensus
Who runs elections hereMadison County Election AdministratorElections here are run by Madison County (county election office). Box 366, Virginia City, MT 59755-0366 · (406) 843-4270 · [email protected]FVAP, Jun 2021
Register to voteIn personMontana has no online registration; you can register in person up to and including Election Day or by mail (postmarked 30 days before).vote.govCheck your registration and polling placeprodvoterportal.mt.govThe state’s voter lookup

Election office: FVAP local election office directory, updated Jun 2021; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.

ZIP codes & area codes

Mammoth is in ZIP code 59721

ZIP codes where Mammoth residents live, with the share of the town in each.

ZIPPost office nameShare of MammothZIP’s residents in Mammoth
59721Cardwell, MT100%1%

Census 2020 ZIP Code Tabulation Areas, by census block; post office names: GeoNames (CC BY 4.0). ZIPs created since 2020 are missing.

Everyday places

Getting around, the ER and the library

One line each; the subject pages have the rest.

Nearest emergency roomRuby Valley Medical Center17.1 miles awayGet a library cardSheridan Public Library109 East Hamilton · (406) 842-5770

ER: CMS hospital data. Library: IMLS Public Libraries Survey, FY2024.

Questions about living in Mammoth

Who provides electricity in Mammoth?

NorthWestern Energy (NorthWestern Energy LLC - (MT)), an investor-owned utility. Its homes paid about 14.4¢ per kWh in 2025 (EIA).

What ZIP codes are in Mammoth?

59721. Census 2020 ZIP Code Tabulation Areas.

What school district is Mammoth in?

Harrison K-12 Schools.

How do I register to vote in Mammoth?

Montana has no online registration; you can register in person up to and including Election Day or by mail (postmarked 30 days before). Elections here are run by the Madison County Election Administrator. Check your registration at prodvoterportal.mt.gov.

Sources & dates

Every answer above names its source. Here they are with their dates.

  • Power: HIFLD Electric Retail Service Territories (map Aug 2023); EIA-861 final 2025.
  • Trash: OpenStreetMap, Geofabrik extract of Oct 9, 2026. © OpenStreetMap contributors (ODbL).
  • ZIP codes: Census 2020 ZCTA relationship files; GeoNames postal codes (CC BY 4.0).
  • Schools: NCES Common Core of Data, 2024–25.
  • Registration: vote.gov, updated Nov 18, 2024 (read Oct 10, 2026). Official sites and area codes: Wikidata.
  • Election office: FVAP local election office directory (fetched Oct 10, 2026; each record dated), EAC EAVS 2024 jurisdictions; registration and lookup links from vote.gov’s state data, checked Oct 10, 2026.
  • Internet (FCC): pending.