Charlestown MA.
Originally called Mishawum - it was designed by engineer Thomas Graves in 1629. It was the first capital of the Massachusetts Bay Colony. Charlestown became a city in 1848 and was annexed by Boston on 5 Jan 1874, thereby changing counties from Middlesex to Essex.
When Charlestown was originally designed it encompassed Somerville, Medford, and the northern part of Arlington. It was also a peninsula, being connected to the mainland at Sullivan Square.