Before the Pilgrims arrived, the site of Plymouth was the Wampanoag village of Patuxet. Samuel de Champlain sailed into the harbor in 1605 and called it Port St. Louis, and Captain John Smith of Jamestown explored Cape Cod Bay and is credited with naming the region New Plimouth. Epidemics in 1614 and 1617 killed 90 to 95 percent of the local Wampanoag, leaving their cornfields and cleared land empty.
More about Plymouth
Plymouth was the final landing place of the Mayflower and the site of the original settlement of Plymouth Colony, founded in December 1620 by separatists who had broken from the Church of England, later called the Pilgrims, a term coined by William Bradford. The Mayflower first anchored at Provincetown on November 11, 1620. It had been bound for the mouth of the Hudson River, and because the settlers had no patent for New England they signed the Mayflower Compact before going ashore. After exploring Cape Cod they found the sheltered harbor of Plymouth on December 17 and disembarked on December 21, 1620. Tradition holds that they first stepped ashore at Plymouth Rock, though no historical evidence supports it.
The colony faced starvation and lack of shelter in its first winter and depended from the start on help from Native Americans. Squanto, who had escaped slavery in Spain and returned home in 1619, taught the colonists to grow corn and fish, and with Hobomok, sent by Massasoit in 1621, he helped them set up fur trading posts, and Massasoit made a peace treaty with the Pilgrims.
Sources
Wikipedia: Plymouth, Massachusetts