Celia Fiennes was born at the family manor of Newton Toney, near Salisbury, in Wiltshire, England, a daughter of Nathaniel Fiennes, a former colonel in the Parliamentary army during the English Civil War, and his second wife Frances Whitehead. After her mother died, she moved to London to live with a married sister. She is remarkable for the journeys on horseback she made, and the account she wrote of them, through every county in England, accompanied only by two servants. In 1697 and 1698 she made two long trips through northern England and Scotland. She travelled "to regain my health by variety and change of aire and exercise" but also out of curiosity and for adventure. Twice she was thrown from her horse when it fell, but was unhurt; such accidents failed to upset or discourage her. Her account of her travels seems to have been written after they had largely ended in 1702. An acute observer, she described the stately homes she visited, the newly-fashionable spa towns such as Bath and Harrogate, the still largely unenclosed countryside with its few and primitive roads, and the developing new industries. During this era, travel for its own sake was a novel idea, and Celia was exceptional as a solo woman traveler. Her travel journal, intended for family reading, was not published during her lifetime. In 1812, Robert Southey published extracts, and the first complete edition appeared in 1888 under the title Through England on a Side Saddle. A scholarly edition called The Illustrated Journeys of Celia Fiennes was edited by Christopher Morris and published in 1947. Since then, the book has remained in print through several editions.
It was adapted into a play called Riding England Sidesaddle by Christopher Goulding, which premiered in Newcastle-upon-Tyne in 1992.