The family compound there, her son Anthony said, shared a wall with the compound of gangster Al Capone.
In 1938, Mrs. Cadwalader first made her mark, by winning the Best Child Rider award at that year's Devon Horse Show, as a 12-year-old horsewoman.
Her interest in horses did not fade.
In 1971, at 45, she helped start the Philadelphia Horse Show at the Spectrum. The event, a society columnist reported, was "the first major indoor horse show to take place in this city in many years."
As chairman of boxes for the October event, Mrs. Cadwalader told the columnist: "I hope the Philadelphia Horse Show won't get like Devon, where you have to practically inherit a box to obtain one.
"Getting a box at our indoor horse show will be as coveted as a dance floor table at the Academy Ball." Her son said the event was relatively short-lived.
In 1974, Mrs. Cadwalader was cochairman of Olde City Sunday in Philadelphia, which the society columnist called "the biggest block party in the history of Philadelphia," helping to highlight, two years early, the 1976 Bicentennial celebration.
Though she lived in Chester County, Mrs. Cadwalader spoke proudly of her birthplace.
"Philadelphia is a part of us," she told a reporter writing about Olde City Sunday. "It's wrong to escape from it. Our roots are here."
Mrs. Cadwalader was a member of Mr. Stewart's Cheshire Foxhounds and the Rose Tree, Brandywine, and Radnor hunts.
While a member of the Kennett Square Golf and Country Club, she helped start the Tenni-Tour, an annual event in which teams went from private tennis court to private tennis court in and near Unionville.
She was a board member of the Newlin Grist Mill in Concord Township; the Primitive Hall Foundation, which preserves a historic home of that name in West Grove; and the Salisbury (Conn.) School.
A member of the West Chester Garden Club, she also did volunteer work for the Academy of Music and the Philadelphia Museum of Art.
Besides her son Anthony, Mrs. Cadwalader is survived by sons Stephen and R. Kent; stepsons Gouverneur 3d and Richard; a sister; eight grandchildren; a niece; and a nephew. Her husband, Gouverneur Cadwalader Jr., died in 2006. She also was preceded in death by her first husband, William McNichol.
A graveside service was set for 11 a.m. Wednesday at West Laurel Hill Cemetery, Bala Cynwyd.
Contact staff writer Walter F. Naedele at 215-854-5607 or email@example.com.