A comma (,) is used between the name of a city and its state or province. The name of the city always comes before the state or province it is in.
Remember, the names of cities and states begin with a capital letter!
Hilo, Hawaii is known as the city of rain and fire.
Rouen, Normandy is one of France's most historic and ancient cities.
Joinville, Santa Catarina is a busy city in Brazil.