Aaron H. Cragin (February 3, 1821 - May 10, 1898) was a United States Representative and Senator from New Hampshire. Born in Weston, Vermont, he completed preparatory studies, studied law, was admitted to the bar in Albany, New York in 1847 and commenced practice in Lebanon, New Hampshire. He was a member of the New Hampshire House of Representatives from 1852 to 1855, and was elected by the American Party to the Thirty-fourth Congress and as a Republican to the Thirty-fifth Congress (March 4, 1855-March 3, 1859). While in the House of Representatives, he was chairman of the Committee on Expenditures in the Department of War (Thirty-fourth Congress).
Cragin resumed the practice of law and in 1859 was again a member of the State house of representatives. He was elected as a Republican to the U.S. in 1864, was reelected in 1870 and served from March 4, 1865, to March 3, 1877. While in the Senate he was chairman of the Committee on Engrossed Bills (Thirty-ninth Congress) and a member of the Committee to Audit and Control the Contingent Expense (Fortieth and Forty-first Congresses), the Committee on Naval Affairs (Forty-first and Forty-third Congresses), and the Committee on Railroads (Forty-third and Forty-fourth Congresses). He was appointed by President Rutherford Hayes as one of the commissioners for the purchase of the Hot Springs Reservation in Arkansas and served as chairman from 1877 to 1879. He died in Washington, D.C. in 1898; interment was in School Street Cemetery, Lebanon, New Hampshire.