The alphamegalog of the cities of Wyoming lists the largest city in Wyoming for each letter of the alphabet. In this case, ‘largest’ is based on population within the city proper.

Afton
Buffalo
Cheyenne
Douglas
Evanston
Fox Farm College
Gillette
Hoback
(no I)
Jackson
Kemmerer
Laramie
Mills
Newcastle
Osmond
Powell
(no Q)
Rock Springs
Sheridan
Torrington
Upton
Vista West
Worland
(no X)
Y O Ranch
(no Z)