Mason, George (1725–1792), a United States statesman of the Revolutionary and early national period. He was a wealthy Virginia planter who usually shunned active politics, but had a major role in shaping national policies by his writings and personal influence. He was a persistent advocate of individual rights. As a member of the Virginia constitutional convention of 1776, Mason largely wrote the constitution and drew up the Declaration of Rights. which was adopted as the state Bill of Rights. Thomas Jefferson used this document when he drafted the Declaration of Independence. Other states copied from Mason, and many of his provisions were adopted in the first 10 amendments (Bill of Rights) of the U.S. Constitution.

Mason promoted George Rogers Clark's expedition of 1778, which conquered the Northwest from the British. He wrote an influential paper in which he demanded that the treaty of peace recognize the Great Lakes, instead of the Ohio River, as the national boundary. Mason sketched the plan under which Virginia ceded its western lands to the United States.

Mason was active in the federal constitutional convention of 1787. However, he refused to sign the Constitution because it had no bill of rights, permitted continuance of the slave trade until 1808, and appeared to place the agrarian South at a disadvantage. Later, in the Virginia convention, he unsuccessfully opposed ratification. (The Bill of Rights was not added until 1791.)

Mason was born in Stafford (now Fairfax) County, Virginia, and was tutored at home. He was active in community affairs, and in the movement toward independence opposed the Stamp Act and Townshend duties. Mason served in the Virginia House of Delegates, 1776–80 and 1786–88. In 1777 he was elected to the Continental Congress but declined to serve, and in 1789 he refused election to the U.S. Senate in the first Congress.