The Plymouth Colony was founded in 1620 by Separatist colonists fleeing from England.
The Separatists were a group of people who left England because they felt that the Church of England was departing from the Scripture. They wanted to found a church that exactly followed the New Testament. A good place to do that was in Holland, a country which welcomed people of all religions.
However, the Separatists wanted to have their English customs back and decided to leave Holland and go to North America. They signed up to the Virginia Company and set sail in the Mayflower.
On the way to the New World, a storm sprung up and drove them from their original destination. To avoid the storm, the settlers had to choose another place to land. They were driven to what is now known as Plymouth Bay, and landed there on December 21, 1620. They made a colony they called Plymouth Colony, and after realizing they didn't have anyone's permission to establish a colony there, they drafted the Mayflower Compact, which was signed by 41 men. The Mayflower Compact was a set of rules that they would follow in governing the colony.
The 41 men who signed the Compact became the town's council members, and they elected John Carver as governor, but he was soon replaced by William Bradford due to Carver's death.
Over half the colony died during the winter, but that spring, the colonists met an English-speaking Indian named Squanto, who introduced them to his tribe, the Wampanoag. The friendly Indians helped the settlers, and that fall, the new colonists made the first Thanksgiving feast for themselves and the tribe.