In 1765 with Samuel Adams, James Otis Jr. and Timothy Ruggles, he was called to represent Massachusetts at the Stamp Act Congress in New York, which resulted in the first official American opposition to British policy. Partridge signed the Declaration of Rights and Grievances to HM King George III and Parliament in which the American Congress respectfully explained their reasons for their opposition to the Act. The Declaration emphasized the colonists' rights as natural born Englishmen with all of the rights and liberties pertaining thereto including the right to trial by jury and representation in matters of taxation. The Stamp Act Congress and its Declaration of Rights eventually resulted in the Stamp Act's repeal in March 1766. It also led the colonists to focus on the idea of constitutional limitations on parliamentary authority, a concept that contributed to the American Revolution. While Partridge was in favor of Benjamin Franklin's proposed colonial union (later the United States) and publicly defended the colonists' English liberties, when he later received a letter from revolutionary leaders in Boston in 1775 as to whether he would take up arms against the mother country he replied that he feared such action might bring the country more harm than good. As matters progressed he reconciled himself to the inevitability of separation from the Britain, and resumed his legal duties as an American patriot. Such was the respect in which he was held by his countrymen that his revolutionary neighbors in the meantime did not molest his person or property during the American Revolutionary War, and in 1780 and 1781 he was again appointed selectman for Hatfield, Massachusetts. His descendants remained active in America politics. His son William Partridge supported the career of his brother-in-law the Hon. Barnabas Bidwell who clerked under his cousin the Hon. Theodore Sedgwick (former Speaker of the House in the George Washington administration) and was elected a Massachusetts Congressman, Senator, Attorney General and U.S. Congressman and administration spokesman for President Thomas Jefferson. Oliver Partridge's great granddaughter Emily Partridge married Utah Governor Brigham Young of the Richards-Young family and his great great grandson Edward Partridge Jr. was a Utah representative and delegate to the Utah Constitutional Convention of 1895. He died at Hadley. His epitaph states that "His usefulness in church and state was early known to men; Blest with an active life, till late, and happy in his end."