An email sent from someone in the CDT time zone will have the time zone listed as "-0500" in the headers of the email. (However, "-0500" does not have to be in CDT, as other time zones could have the same UTC offset).
- Alabama
- Arkansas
- Florida - North-West parts
Bay, Calhoun, Escambia, Holmes, Jackson, Okaloosa, Santa Rosa, Walton and Washington counties and norther Gulf county
- Illinois
- Indiana - these few north-western counties near Chicago
Lake, Porter, La Porte, Newton, Jasper, Starke
and these south-western counties in Indiana near Evansville Gibson, Posey, Vanderburgh, Warrick, Perry
- Iowa
- Kansas - except these western counties
Greeley, Hamilton, Sherman and Wallace -
MST/
MDT
- Kentucky - Western part
Adair, Allen, Ballard, Barren, Breckinridge, Butler, Caldwell, Calloway, Carlisle, Christian, Clinton, Crittenden, Cumberland, Daviess, Edmonson, Fulton, Graves, Grayson, Green, Hansock, Hart, Henderson, Hickman, Hopkins, Livingston, Logan, Lyon, Marshall, McCracken, McLean, Metcalfe, Monroe, Muhlenberg, Ohio, Russell, Simpson, Todd, Trigg, Union, Warren and Webster counties
- Louisiana
- Michigan - A few western counties
Dickinson, Gogebic, Iron, and Menominee
- Minnesota
- Mississippi
- Missouri
- Nebraska - Eastern parts
All except Arthur, Banner, Box Butte, Chase, Cheyenne, Dawes, Deuel, Dundy, Garden, Grant, Hooker, Keith, Kimball, Morrill, Perkins, Scotts Bluff, Sheridan, and Sioux counties and the western part of Cherry county which are on
MST/
MDT
- North Dakota - North and Eastern parts
counties of Barnes, Benson, Bottineau, Burke, Burleigh, Cass, Cavalier, Dickey, Divide, Eddy, Emmons, Foster, Grand Forks, Griggs, Kidder, Lamoure, Logan, McHenry, McIntosh, McLean, Mountrail, Nelson, Oliver, Pembina, Pierce, Ramsey, Ransom, Renville, Richland, Rolette, Sargent, Sheridan, Steele, Stutsman, Towner, Traill, Walsh, Ward, Wells, Williams and northern parts of McKenzie and Dunn, westernmost part of Morton and Fort Yates in Sioux
- Oklahoma
- South Dakota - Eastern parts
counties of Aurora, Beadle, Bon Homme, Brookings, Brown, Brule, Buffalo, Campbell, Charles Mix, Clark, Clay, Codington, Davison, Day, Deuel, Douglas, Edmunds, Faulk, Grant, Gregory, Hamlin, Hand, Hanson, Hughes, Hutchinson, Hyde, Jerauld, Kingsbury, Lake, Lincoln, Lyman, Marshall, McCook, McPherson, Miner, Minnehaha, Moody, Potter, Roberts, Spink, Sanborn, Sully, Tripp, Turner, Union, Yankton, Walworth and eastern parts of Jones and Stanley
- Tennessee - Western part
counties of Bedford, Benton, Bledsoe, Cannon, Carroll, Cheatham, Chester, Clay, Coffee, Crockett, Cumberland, Davidson, Decatur, DeKalb, Dickson, Dyer, Fayette, Fentress, Franklin, Gibson, Giles, Grundy, Hardeman, Hardin, Haywood, Henderson, Henry, Hickman, Houston, Humphreys, Jackson, Lake, Lauderdale, Lawrence, Lewis, Lincoln, McNairy, Macon, Madison, Marion, Marshall, Maury, Montgomery, Moore, Obion, Overton, Perry, Pickett, Putnam, Robertson, Rutherford, Sequatchie, Shelby, Smith, Stewart, Sumner, Tipton, Trusdale, Van Buren, Warren, Wayne Weakley, White, Willamson, Wilson
- Texas - All, but a few counties in west
El Paso and Hudspeth and part of Culberson
- Wisconsin
