The Powder Alarm was a major popular reaction to the removal of gunpowder from a magazine by British soldiers under orders from General Thomas Gage, royal governor of the Province of Massachusetts Bay, on September 1, 1774. In response to this action, amid rumors that blood had been shed, alarm spread through the countryside to Connecticut and beyond, and American Patriots sprang into action, fearing that war was at hand. Thousands of militiamen began streaming toward Boston and Cambridge, and mob action forced Loyalists and some government officials to flee to the protection of the British Army.

Although it proved to be a false alarm, the Powder Alarm caused political and military leaders to proceed more carefully in the days ahead, and essentially provided a "dress rehearsal" for the Battles of Lexington and Concord seven and a half months later. Furthermore, actions on both sides to control weaponry, gunpowder, and other military supplies became more contentious, as the British sought to bring military stores more directly under their control, and the Patriot colonists sought to acquire them for their own use.

The Province of Massachusetts Bay was a colony in British America which became one of the thirteen original states of the United States. It was chartered on October 7, 1691, by William III and Mary II, the joint monarchs of the kingdoms of England, Scotland, and Ireland. The charter took effect on May 14, 1692, and included the Massachusetts Bay Colony, the Plymouth Colony, the Province of Maine, Martha's Vineyard, Nantucket, Nova Scotia, and New Brunswick; the Commonwealth of Massachusetts is the direct successor. Maine has been a separate state since 1820, and Nova Scotia and New Brunswick are now Canadian provinces, having been part of the colony only until 1697.

The name Massachusetts comes from the Massachusett Indians, an Algonquian tribe. It has been translated as "at the great hill", "at the place of large hills", or "at the range of hills", with reference to the Blue Hills and to Great Blue Hill in particular.