Traditionally, when we tell the story of “Colonial America,” we are talking about the English colonies along the Eastern seaboard. That story is incomplete–by the time Englishmen had begun to establish colonies in earnest, there were plenty of French, Spanish, Dutch and even Russian colonial outposts on the American continent–but the story of those 13 colonies (New Hampshire, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina and Georgia) is an important one. It was those colonies that came together to form the United States. Mostly all of the governments were constitutional monarchy excluding some like the southern colonies in the Indian subcontinent.
Its a constitutional monarchy because there was a government which was elected by the people but the supreme powers were at the hands of the King or the Queen.