The Darlingtons of Pittsburgh trace their roots in America to Abraham Darlington of Cheshire County, England, who joined his aunt and uncle in Chester County, Pennsylvania, at the turn of the eighteenth century. Abraham's great-grandson, Benjamin Darlington (1820-1852), left Chester County and settled in Pittsburgh with his wife, Agnes McCullough. The Darlingtons of Pittsburgh are related to the Schenley and O'Hara families through the marriage of Benjamin and Agnes's son, William McCullough Darlington (1815-1889), to Mary Carson O'Hara. William M. Darlington was a successful lawyer and one of the foremost experts in the colonial history of western Pennsylvania and the Ohio Valley. Mary shared her husband's passion for history, and was very proud of her family's ancestry, which she traced back to Irish nobility through her grandfather, James O'Hara. Through her father, Mary inherited Guyasuta, James O'Hara's estate near present-day Sharpsburg, Pennsylvania. William and Mary raised three children at Guyasuta, O'Hara, Mary, and Edith. A fourth child, Hillborn, died in childhood. For more detailed biographies of each family member, see the scope and content note provided for each individual's papers. William was the primary collector of his family's extensive library of books and manuscripts. After William's death in 1889, his widow and children maintained and added to his collection. In 1918 and 1925, William's daughters Edith and Mary donated the family library and manuscript collection to the University of Pittsburgh. These materials now reside in the Darlington Memorial Library in the Cathedral of Learning, including original letters by George Washington, Colonel Henry Bouquet, General Anthony Wayne, Hugh Henry Brackenridge, General Cornwallis, General James Wilkinson, Alexander Hamilton, Andrew Jackson and Daniel Webster. William M. Darlington also obtained and preserved J. J. Audubon's complete Set of Birds of America.
From the description of Darlington family papers, 1753-1921 [electronic resource]. (University of Pittsburgh). WorldCat record id: 671386919