John Stewart “J.S.” McLennan (1853-1939) was a Montreal-born industrialist, historian and publisher who first came to Cape Breton Island to manage the early coal and steel industries of the area. He married artist Louise Ruggles Bradley of Chicago in 1881 and together they welcomed five children into the world - Frances, Isabel, Hugh, Margaret, and Katharine.

By 1898, J.S. was prepared to retire from industrial life and move the young McLennan family to Sydney permanently. They lived in several residences during their early Cape Breton years, including Havenside in Louisbourg and Brookdale in South Bar, but none as grand as Petersfield, their Westmount estate, built in 1902. The McLennans enjoyed many happy years at Petersfield, entertaining visiting dignitaries and famous guests, as well as beloved friends and relatives.

Once settled at Petersfield, J.S. embarked on a lifelong pursuit of uncovering the history of the Fortress of Louisbourg. With research assistance from Louise and Katharine, he wrote the seminal text, Louisbourg From Its Foundation to Its Fall. Louise was an accomplished artist and one of the founding members of the Sydney Painters' Club, one of the earliest artist associations on the Island. The family suffered a terrible loss when Louise was stricken with appendicitis and died at the age of 51 on February 27, 1912.

Isabel married John S. Farley in 1911 and settled in Massachusetts. Hugh studied arts at McGill University and later architecture at the École des Beaux-Arts in Paris. In 1913, Margaret married Dr. Henry Ernest Kendall, who was named Lieutenant-Governor of Nova Scotia in 1942. Tragedy befell the McLennans during the early years of the First World War; Hugh enlisted in the Canadian Field Artillery in 1914 and was killed at Ypres on April 26, 1915. Following the death of her brother, Katharine felt the call to do her part in the war effort. She served overseas as a volunteer with the Red Cross in France in 1916, the same year that her father was called to the Senate. After her return from the War, Katharine continued to work with her father in researching and soliciting government investment in the Fortress of Louisbourg site.

The McLennan family, through their contributions to Cape Breton’s arts, culture and heritage community, made a lasting impact on the island that is still widely recognized today.