Why did the Thirteen Colonies declare independence?

The thirteen British colonies in North America declared independence for a few reasons. The decision to declare independence, however, was not welcomed by all segments of the colonial population. Those Americans who remained loyal to Britain were known as Loyalists, and they may have made up as much one-third of the population.
Britain and its colonies on the Eastern seaboard of North America got along relatively well for more than a century. The trading relationship between the two—based on mercantilism—favored London, but the colonies and mother country were linked by a common culture, language, and history.
Britain defeated France in 1763 and expelled the French from North America. After that, the relationship soured. The colonists realized that they no longer needed British protection, but London insisted on keeping garrisons of its troops in the colonies. Also, a number of new and unpopular taxes were introduced in North America. There were also violent incidents, like the Boston Tea party and the Boston Massacre.
The first battle occurred by accident at Lexington and Concord in 1775. One year later, the colonists declared independence.