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

Ashaway
Bradford
Cranston
(no D)
East Providence
Foster
Greenville
Hope Valley
(no I)
Johnston
Kingston
Lincoln
Middletown
Newport
(no O)
Providence
Quonochontaug
Riverside
South Kingstown
Tiverton
(no U)
Valley Falls
Warwick
(no X)
(no Y)
(no Z)