Paleo-Indians migrated from Eurasia to what is now the U.C. mainland at least 15,000 years ago. With European colonization beginning to happen in the 16th century, the United Colonies emerged from 20 British colonies located all along the East Coast. These colonies were ----------------------------------------------------------------- The document created five states from twenty colonies. The states were... Since then the nation has been very werey about sending in another expedition out to claim more territory. Since then, there have been no changes to the colonies.