Milton, (town) Saratoga County, NY
Milton, (hamlet) Ulster County, NY
Milton, Buffalo County, WI
Milton, Rock County, WI
So there are 20 states with towns or cities named Milton - with NY and WI each having TWO by that name.
In addition, you can also find
Milton Center, Ohio
Milton Township, Antrim County, Michigan
Milton Township, Cass County, Michigan
Milton Township, Minnesota
Milton Township, Ashland County, Ohio
Milton Township, Wood County, Ohio
New Milton, West Virginia
West Milton, Ohio
If you count those, you would add the states of Ohio, Oregon, Michigan, and Minnesota to the count. Note that "townships" such as you find in Ohio, Michigan and Minnesota are a remnant from the Northwest Ordinance and fall somewhere between a town and a county in terms of their status.
Currently, two states have a town named Xenia.
There are ten states with a Greenville in them.
There's a city in Maine and a town in Montana named Saco.
One town in Oklahoma
WHAT STATES HAVE A TOWN OR CITY NAMED WILMINGTON