The first wave of classicism in US city-names was inspired by the self-conscious republicanism of American citizens. Eg, George Washington was compared to the Roman general "Cincinnatus" (a savior of the republic), some veterans of his campaigns formed the "Order of Cincinnatus", and the city of Cincinnati was named on the same principle in 1788.

The second wave was inspired by the Greek War of Independence, circa 1819-1825. For obvious reasons there was a lot of sympathy for the Greeks in the USA, and the hellenomania of this generation gave us the names around the Finger Lakes and Rochester.

Later, as settlers continued to move westward, they often brought the names of their hometowns to the frontier. For example there are something like a dozen Utica's in the US - four in Wisconsin alone!

Adding on, why is this also the case with upstate NY? Utica, Ithaca, Syracuse, etc.