StacksVerified U.S. regulatory reference

40 CFR Part 81, Appendix A

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗

| AQCR No.

Alabama: |

Alabama and Tombigbee Rivers1
Columbus-Phenix City2
East Alabama3
Metropolitan Birmingham4
Mobile-Pensacola-Panama City-Southern Mississippi (Fla., Miss.)5
Southeast Alabama6
Tennessee River Valley-Cumberland Mountains (Tenn.)7

Alaska: |

Cook Inlet8
Northern Alaska9
South Central Alaska10
Southeastern Alaska11

Arizona: |

Arizona-New Mexico Southern Border (N. Mex.)12
Clark-Mohave13
Four Corners (Colo., N. Mex., Utah)14
Phoenix-Tucson15

Arkansas: |

Central Arkansas16
Metropolitan Fort Smith17
Metropolitan Memphis18
Monroe-El Dorado (La.)19
Northeast Arkansas20
Northwest Arkansas21
Shreveport-Texarkana-Tyler (La., Okla., Texas)22

California: |

Great Basin Valley23
Metropolitan Los Angeles24
North Central Coast25
North Coast26
Northeast Plateau27
Sacramento Valley28
San Diego29
San Francisco Bay Area30
San Joaquin Valley31
South Central Coast32
Southeast Desert33

Colorado: |

Comanche34
Four Corners (Ariz., N. Mex., Utah)14
Grand Mesa35
Metropolitan Denver36
Pawnee37
San Isabel38
San Luis39
Yampa40

Connecticut: |

Eastern Connecticut41
Hartford-New Haven-Springfield (Mass.)42
New Jersey-New York-Connecticut (N.J., N.Y.)43
Northwestern Connecticut44

Delaware: |

Metropolitan Philadelphia (N.J., Pa.)45
Southern Delaware46

District of Columbia: |

National Capital (Md.) | 47

Florida: |

Central Florida48
Jacksonville-Brunswick (Ga.)49
Mobile-Pensacola-Panama City-Southern Mississippi (Ala., Miss.)5
Southeast Florida50
Southwest Florida51
West Central Florida52

Georgia: |

Augusta-Aiken (S.C.)53
Central Georgia54
Chattanooga (Tenn.)55
Columbus-Phenix City (Ala.)2
Jacksonville-Brunswick (Fla.)49
Metropolitan Atlanta56
Northeast Georgia57
Savannah-Beaufort (S.C.)58
Southwest Georgia59

Hawaii: |

Entire State | 60

Idaho: |

Eastern Idaho61
Eastern Washington-Northern Idaho (Wash.)62
Idaho63
Metropolitan Boise64

Illinois: |

Burlington-Keokuk (Iowa)65
East Central Illinois66
Metropolitan Chicago (Ind.)67
Metropolitan Dubuque (Iowa, Wis.)68
Metropolitan Quad Cities (Iowa)69
Metropolitan St. Louis (Mo.)70
North Central Illinois71
Paducah-Cairo (Ky.)72
Rockford-Janesville-Beloit (Wis.)73
Southeast Illinois74
West Central Illinois75

Indiana: |

East Central Indiana76
Evansville-Owensboro-Henderson (Ky.)77
Louisville (Ky.)78
Metropolitan Chicago (Ill.)67
Metropolitan Cincinnati (Ky., Ohio)79
Metropolitan Indianapolis80
Northeast Indiana81
South Bend-Elkhart-Benton Harbor (Mich.)82
Southern Indiana83
Wabash Valley84

Iowa: |

Burlington-Keokuk (Ill.)65
Metropolitan Dubuque (Ill., Wis.)68
Metropolitan Omaha-Council Bluffs (Nebr.)85
Metropolitan Quad Cities (Ill.)69
Metropolitan Sioux City (Nebr., S. Dak.)86
Metropolitan Sioux Falls (S. Dak.)87
Northeast Iowa88
North Central Iowa89
Northwest Iowa90
Southeast Iowa91
South Central Iowa92
Southwest Iowa93

Kansas: |

Metropolitan Kansas City (Mo.)94
Northeast Kansas95
North Central Kansas96
Northwest Kansas97
Southeast Kansas98
South Central Kansas99
Southwest Kansas100

Kentucky: |

Appalachian101
Bluegrass102
Evansville-Owensboro-Henderson (Ind.)77
Huntington-Ashland-Portsmouth-Ironton (Ohio, W. Va.)103
Louisville (Ind.)78
Metropolitan Cincinnati (Ind., Ohio)79
North Central Kentucky104
Paducah-Cairo (Ill.)72
South Central Kentucky105

Louisiana: |

Monroe-El Dorado (Ark.)19
Shreveport-Texarkana-Tyler (Ark., Okla., Tex.)22
Southern Louisiana-Southeast Texas (Tex.)106

Maine: |

Androscoggin Valley (N.H.)107
Aroostook108
Down East109
Metropolitan Portland110
Northwest Maine111

Maryland: |

Central Maryland112
Cumberland-Keyser (W. Va.)113
Eastern Shore114
Metropolitan Baltimore115
National Capital (D.C.)47
Southern Maryland116

Massachusetts: |

Berkshire117
Central Massachusetts118
Hartford-New Haven-Springfield (Conn.)42
Metropolitan Boston119
Metropolitan Providence (R.I.)120
Merrimack Valley-Southern New Hampshire (N.H.)121

Michigan: |

Central Michigan122
Metropolitan Detroit-Port Huron123
Metropolitan Toledo (Ohio)124
South Bend-Elkhart-Benton Harbor (Ind.)82
South Central Michigan125
Upper Michigan126

Minnesota: |

Central Minnesota127
Southeast Minnesota-La Crosse (Wis.)128
Duluth-Superior (Wis.)129
Metropolitan Fargo-Moorhead (N. Dak.)130
Minneapolis-St. Paul131
Northwest Minnesota132
Southwest Minnesota133

Mississippi: |

Metropolitan Memphis (Ark., Tenn.)18
Mississippi Delta134
Mobile-Pensacola-Panama City-Southern Mississippi (Ala., Fla.)5
Northeast Mississippi135

Missouri: |

Metropolitan Kansas City (Kans.)94
Metropolitan St. Louis (Ill.)70
Northern Missouri137
Southeast Missouri138
Southwest Missouri139

Montana: |

Billings140
Great Falls141
Helena142
Miles City143
Missoula144

Nebraska: |

Lincoln-Beatrice-Fairbury145
Metropolitan Omaha-Council Bluffs (Iowa)85
Metropolitan Sioux City (Iowa, S. Dak.)86
Nebraska146

Nevada: |

Clark-Mohave (Ariz.)13
Nevada147
Northwest Nevada148

New Hampshire: |

Androscoggin Valley (Maine)107
Merrimack Valley-Southern New Hampshire (Mass.)121
New Hampshire149

New Jersey: |

Metropolitan Philadelphia (Del., Pa.)45
New Jersey150
New Jersey-New York-Connecticut (N.Y., Conn.)43
Northeast Pennsylvania-Upper Delaware Valley (Pa.)151

New Mexico: |

Albuquerque-Mid Rio Grande152
Arizona-New Mexico Southern Border (Ariz.)12
El Paso-Las Cruces-Alamogordo (Tex.)153
Four Corners (Ariz., Colo., Utah)14
Northeastern Plains154
Pecos-Permian Basin155
Southwestern Mountains-Augustine Plains156
Upper Rio Grande Valley157

New York: |

Central New York158
Champlain Valley (Vt.)159
Genesee-Finger Lakes160
Hudson Valley161
New Jersey-New York-Connecticut (N.J., Conn.)43
Niagara Frontier162
Southern Tier East163
Southern Tier West164

North Carolina: |

Eastern Mountain165
Eastern Piedmont166
Metropolitan Charlotte (S.C.)167
Northern Coastal Plain168
Northern Piedmont136
Sandhills169
Southern Coastal Plain170
Western Mountain171

North Dakota: |

Metropolitan Fargo-Moorhead (Minn.)130
North Dakota172

Ohio: |

Dayton173
Greater Metropolitan Cleveland174
Huntington-Ashland-Portsmouth-Ironton (Ky., W. Va.)103
Mansfield-Marion175
Metropolitan Cincinnati (Ind., Ky.)79
Metropolitan Columbus176
Metropolitan Toledo (Mich.)124
Northwest Ohio177
Northwest Pennsylvania-Youngstown (Pa.)178
Parkersburg-Marietta (W. Va.)179
Sandusky180
Steubenville-Weirton-Wheeling (W. Va.)181
Wilmington-Chillicothe-Logan182
Zanesville-Cambridge183

Oklahoma: |

Central Oklahoma184
Metropolitan Fort Smith (Ark.)17
North Central Oklahoma185
Northeastern Oklahoma186
Northwestern Oklahoma187
Shreveport-Texarkana-Tyler (Ark., La., Texas)22
Southeastern Oklahoma188
Southwestern Oklahoma189

Oregon: |

Central Oregon190
Eastern Oregon191
Northwest Oregon192
Portland (Wash.)193
Southwest Oregon194

Pennsylvania: |

Central Pennsylvania195
Metropolitan Philadelphia (Del., N.J.)45
Northeast Pennsylvania-Upper Delaware Valley (N.J.)151
Northwest Pennsylvania-Youngstown (Ohio)178
South Central Pennsylvania196
Southwest Pennsylvania197

Rhode Island: |

Metropolitan Providence (Mass.) | 120

South Carolina: |

Augusta-Aiken (Ga.)53
Camden-Sumter198
Charleston199
Columbia200
Florence201
Greenville-Spartanburg202
Greenwood203
Georgetown204
Metropolitan Charlotte (N.C.)167
Savannah-Beaufort (Ga.)58

South Dakota: |

Black Hills-Rapid City205
Metropolitan Sioux City (Iowa, Neb.)86
Metropolitan Sioux Falls (Iowa)87
South Dakota206

Tennessee: |

Chattanooga (Ga.)55
Eastern Tennessee-Southwestern Virginia (Va.)207
Metropolitan Memphis (Ark., Miss.)18
Middle Tennessee208
Tennessee River Valley-Cumberland Mountains (Ala.)7
Western Tennessee209

Texas: |

Abilene-Wichita Falls210
Amarillo-Lubbock211
Austin-Waco212
Brownsville-Laredo213
Corpus Christi-Victoria214
El Paso-Las Cruces-Alamagordo (N. Mex.)153
Metropolitan Dallas-Ft. Worth215
Metropolitan Houston-Galveston216
Metropolitan San Antonio217
Midland-Odessa-San Angelo218
Shreveport-Texarkana-Tyler (Ark., La., Okla.)22
Southern Louisiana-Southeast Texas (La.)106

Utah: |

Four Corners (Ariz., Colo., N. Mex.)14
Utah219
Wasatch Front220

Vermont: |

Champlain Valley (N.Y.)159
Vermont221

Virginia: |

Central Virginia222
Eastern Tennessee-Southwestern Virginia (Tenn.)207
Hampton Roads223
National Capital (D.C., Md.)47
Northeastern Virginia224
State Capital225
Valley of Virginia226

Washington: |

Eastern Washington-Northern Idaho (Idaho)62
Northern Washington227
Olympia-Northwest Washington228
Portland (Ore.)193
Puget Sound229
South Central Washington230

West Virginia: |

Allegheny231
Central West Virginia232
Cumberland-Keyser (Md.)113
Eastern Panhandle233
Huntington-Ashland-Portsmouth-Iron- ton (Ky., Ohio)103
Kanawha Valley234
North Central West Virginia235
Parkersburg-Marietta (Ohio)179
Southern West Virginia236
Steubenville-Wierton-Wheeling (Ohio)181

Wisconsin: |

Duluth-Superior (Minn.)129
Lake Michigan237
Metropolitan Dubuque (Ill., Iowa)68
North Central Wisconsin238
Rockford- Janesville- Beloit (Ill.)73
Southeastern Wisconsin239
Southeast Minnesota- La Crosse (Minn.)128
Southern Wisconsin240

Wyoming: |

Casper241
Metropolitan Cheyenne242
Wyoming243

Puerto Rico: |

Puerto Rico | 244

American Samoa: |

American Samoa | 245

Guam: |

Guam | 246

U.S. Virgin Islands: |

U.S. Virgin Islands | 247