The Mayflower Compact was signed and thus both “ratified” and put into effect on November 21, 1620 (New Style), which corresponds to November 11, 1620 in the Old Style calendar used at the time. It immediately served as the governing framework for the Plymouth Colony and remained in force until 1691, when Plymouth was absorbed into the Massachusetts Bay Colony.

Key facts at a glance

  • Signing (ratification) date: November 21, 1620 (New Style) / November 11, 1620 (Old Style).
  • Place: Aboard the ship Mayflower while anchored off Cape Cod (near present‑day Provincetown Harbor, Massachusetts).
  • Function: First written framework of self‑government enacted in what became the United States.
  • Period in force: From November 1620 until the Plymouth Colony was merged into Massachusetts Bay in 1691.

Because the Compact was both agreed to, signed, and used as the colony’s governing basis at the same moment, historians typically treat the signing date as the date it was ratified and enacted.