In some cases the standard-setting part includes requirements or other specifications that apply for high-altitude counties. The following counties have substantial populated areas above 4,000 feet above sea level and are therefore considered to be high-altitude counties:

STATE OF ARIZONA Apache Cochise Coconino Navajo Yavapai STATE OF COLORADO Adams Alamosa Arapahoe Archuleta Boulder Chaffee Cheyenne Clear Creek Conejos Costilla Crowley Custer Delta Denver Dolores Douglas Eagle Elbert El Paso Fremont Garfield Gilpin Grand Gunnison Hinsdale Huerfano Jackson Jefferson Kit Carson Lake La Plata Larimer Las Animas Lincoln Mesa Mineral Moffat Montezuma Montrose Morgan Otero Ouray Park Pitkin Pueblo Rio Blanco Rio Grande Routt Saguache San Juan San Miguel Summit Teller Washington Weld STATE OF IDAHO Bannock Bear Lake Bingham Blaine Bonneville Butte Camas Caribou Cassia Clark Custer Franklin Fremont Jefferson Lemhi Madison Minidoka Oneida Power Teton Valley STATE OF MONTANA Beaverhead Deer Lodge Gallatin Jefferson Judith Basin Powell Madison Meagher Park Silver Bow Wheatland STATE OF NEBRASKA Banner Cheyenne Kimball Sioux STATE OF NEVADA Carson City Douglas Elko Esmeralda Eureka Humboldt Lander Lincoln Lyon Mineral Nye Pershing Storey Washoe White Pine STATE OF NEW MEXICO Bernalillo Catron Colfax Curry De Baca Grant Guadalupe Harding Hidalgo Lincoln Los Alamos Luna McKinley Mora Otero Rio Arriba Roosevelt Sandoval San Juan San Miguel Santa Fe Sierra Socorro Taos Torrance Union Valencia STATE OF OREGON Harney Lake Klamath STATE OF TEXAS Jeff Davis Judspeth Parmer STATE OF UTAH Beaver Box Elder Cache Carbon Daggett Davis Duchesne Emery Garfield Grand Iron Juab Kane Millard Morgan Piute Rich Salt Lake San Juan Sanpete Sevier Summit Tooele Uintah Utah Wasatch Wayne Weber STATE OF WYOMING Albany Campbell Carbon Converse Fremont Goshen Hot Springs Johnson Laramie Lincoln Natrona Niobrara Park Platte Sublette Sweetwater Teton Uinta Washakie Weston [73 FR 59344, Oct. 8, 2008. Redesignated at 88 FR 4718, Jan. 24, 2023]