In 1822, the citizens of Boston voted to change the official name from "the Town of Boston" to "the City of Boston", and on March 4, 1822, the people of Boston accepted the charter incorporating the City. At the time Boston was chartered as a city, the population was about 46,226, while the area of the city was only 4.7 square miles (12 km2).
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What year was the name changes to the City of Boston?
1822