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

Ames
Bettendorf
Cedar Rapids
Des Moines
Estherville
Fort Dodge
Grinnell
Hiawatha
Iowa City
Johnston
Keokuk
Le Mars
Marian
Newton
Ottumwa
Pella
Quasqueton
Red Oak
Souix City
Tipton
Urbandale
Vinton
Waterloo
Xenia
Yale
Zearing