Strange what you can learn on the British 'Who Wants to be a Millionaire ?' TV quiz St Augustine, Florida is the oldest city in the USA. How come? What are, or were, the criteria for a place to be a 'city' in the US? Does not any settlement of any identifiable community qualify ? Florida seems an unlikely state to have this honour ( offered such likely and old places as New Hampshire and Virginia the contestant wisely got suspicious and didn't risk an answer ) Why were there not cities in such states as these before Florida got its first ? How do you define a town ? (In Britain this question is technical and easy only to the most knowledgeable: a city has to have a Royal Charter, so a town could have hundreds of thousands of residents and be just a town ,not a city, yet a small town might be one.So Blackburn in Lancashire is not a city yet has well over 130,000 inhabitants. St David's, in Wales, is a city but has only about 1,600. Can't think that Americans have such a bizarre rule )
The Spanish settled Florida before the British settled Virginia (or anywhere else). Digging around a bit online, St. Augustine appears to have been the first continuous European settlement in what is now the US (The Spanish had some earlier failed settlements in the locations of present-day cities).
As far as what makes a city a city over here, it varies, as so much does, from state to state.