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

Albany
Beaverton
Corvalis
Dallas
Eugene
Forest Grove
Gresham
Hillsboro
Independence
Junction City
Keizer
Lake Oswego
Medford
Newburg
Oregon City
Portland
(no Q)
Redmond
Salem
Tigard
Umatilla
Veneta
West Linn
(no X)
Yoncalla
(no Z)