40 CFR § 81.170 - Miles City Intrastate Air Quality Control Region.
---
identifier: "/us/cfr/t40/s81.170"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 81.170 - Miles City Intrastate Air Quality Control Region."
title_number: 40
title_name: "Protection of Environment"
section_number: "81.170"
section_name: "Miles City Intrastate Air Quality Control Region."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "81"
part_name: "DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401,"
regulatory_source: "36 FR 22421, Nov. 25, 1971, unless otherwise noted."
cfr_part: "81"
---
# 81.170 Miles City Intrastate Air Quality Control Region.
The Miles City Intrastate Air Quality Control Region (Montana) consists of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of all municipalities (as defined in section 302(f) of the Clean Air Act, 42 U.S.C. 1857h(f)) geographically located within the outermost boundaries of the area so delimited):
In the State of Montana: Carter County, Custer County, Daniels County, Dawson County, Fallon County, Garfield County, McCone County, Phillips County, Powder River County, Prairie County, Richland County, Roosevelt County, Rosebud County, Sheridan County, Treasure County, Valley County, Wibaux County.