Hi there, and welcome to JA!
Yalesville is a village within the town of Wallingford.
However, some of these places are even smaller than Yalesville, and they can be called "hamlets".
http://en.wikipedia.org/wiki/Yalesville , http://en.wikipedia.org/wiki/Hamlet_%28place%29
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There are many words that could describe it... Yalesville is definitely a "village", but other places might be called hamlets, boroughs, or even townships.