Mary Dimmick Harrison (April 30, 1858 – January 5, 1948) was the second wife of the 23rd United States president Benjamin Harrison. She was 25 years younger than Harrison, and was the niece of his first wife

Born in Honesdale, Pennsylvania as Mary Scott Lord, she was the daughter of Russell Farnham Lord, chief engineer of the Delaware and Hudson Canal (later known as the Delaware and Hudson Railway), and his wife Elizabeth Mayhew Scott.[1]

On October 22, 1881, she married Walter Erskine Dimmick (July 4, 1856 - January 14, 1882), a son of the attorney-general of Pennsylvania and brother of future Scranton mayor J. Benjamin Dimmick. He died three months after their marriage, leaving her a widow at age 23.[1] A niece of Carrie Harrison, she in 1889 moved into the White House to serve as assistant to the First Lady. Sometime after Mrs. Harrison's death in 1892, the former president and Mrs. Dimmick fell in love and late in 1895 announced their engagement.

At age 37, she married the former president, aged 62, on April 6, 1896 at St. Thomas Protestant Episcopal Church in New York City.[1][2] Harrison's grown children from his first marriage, horrified at the news, did not attend the wedding. Harrison's vice president, Levi P. Morton, and several former cabinet members were among the three dozen guests; former navy secretary Benjamin F. Tracy was best man. Without a honeymoon, the couple settled in Indianapolis.

Together, the Harrisons had one daughter:

Elizabeth (Harrison) Walker (1897–1955), a lawyer. Born in Indianapolis, she graduated from New York University law school in 1919. In 1922, she married James Blaine Walker, grandnephew of her father's secretary of state James G. Blaine. She was founder and publisher of "Cues on the News", an investment newsletter for women.

The Harrisons traveled widely: to Venezuela, where Harrison played a role in settling a boundary dispute, and to the First Peace Conference at The Hague in 1899. Mrs. Harrison survived the former president by nearly half a century. Arden Davis Melick reveals that "Mary Dimmick Harrison established The Benjamin Harrison Memorial Home in Indianapolis, Indiana."[3] On September 1, 1914, Mary and her seventeen-year old daughter Elizabeth returned from Europe upon the outbreak of war aboard the Ryndam.[4]

She died in New York City on January 5, 1948 from her asthma.[1][5] She was buried in Indianapolis, Indiana in Crown Hill Cemetery.