Nathaniel Ramsey (May 1, 1741– October 23, 1817) was an American lawyer and soldier from Cecil County, Maryland. Ramsey fought in the Revolutionary War, and was a member of the Congress of the Confederation.
Ramsey was born in Lancaster County, Pennsylvania. He was the elder brother of David Ramsay, though the brothers spelled their name differently. He graduated from the College of New Jersey (later Princeton University) in 1767 and then read law. He settled in northeastern Maryland, and was admitted to the bar in Cecil County in 1771. Ramsey was married to Margaret Jane Peale, known to her family as Jenny, about 1771. Margaret Jane Peale Ramsey often followed the Continental Army following the Battle of Brooklyn.
He was the brother-in-law of artist Charles Willson Peale, who is best remembered for his portrait paintings of leading figures of the American Revolution and for establishing one of the first museums in the United States.
Ramsey was a delegate to the Maryland Convention (the revolutionary assembly) in 1775. In 1776 he joined the Continental Army as a captain in Colonel Smallwood's 1st Maryland Regiment, and went north in time to see action in the Battle of Long Island in August. In December he was promoted to lieutenant colonel and placed in command of the 3rd Maryland Regiment. He led them in the defense of Philadelphia in 1777.