The property at 300 Cambria Street was severed from the lot containing 306 Cambria, where the current house was built in 1909 by Richard Sillifant, a boilermaker.

Harry Dempsey was born in Downie Township, Perth County on April 14, 1884, the fourth of nine children born to Daniel D. Dempsey (1846-1924) and Margaret Laidlaw Armstrong (1852-1907). Daniel was born in Downie Township to Irish parents. Margaret was born in Scotland. Harry’s parents were farmers until they moved to Stratford shortly after his birth. His father then established a greenhouse where he raised flowers and vegetables for sale. He was listed as a gardener or nurseryman-farmer in documents and was described as a prominent horticulturist in his obituary. He was also a member of city council and the park board.

In the 1901 census Harry (at 17 years of age) is listed as a bookkeeper. After graduating from the Stratford Collegiate Institute and Central Business College, Harry began his almost 47-year-long employment with the Whyte Packing Company, a meat-packing company founded in 1859 which became so successful that it opened the largest and most modern meat processing plant in Canada on July 1, 1900. This plant was located on Linden Street near Erie Street, and there were six retail stores: two in Stratford, and one in Toronto, Montreal, Mitchell, and St. Marys. Harry began his career when the plant was two years old and he worked in all departments of the plant for the next 14 years prior to assuming the position of secretary-treasurer. He retired in January 1949, having worked for the same company since 1902.

On February 14, 1914 Harry married Janet Wyllie Kennedy in Stratford. Janet was born on May 27, 1888 in Hamilton to John Kennedy and Sarah McCready, both born in Scotland in 1851. Janet was the youngest of six children. By the time Janet was three her family had moved to Stratford.

Harry and Janet moved into their new house at 300 Cambria Street within a few months of their wedding. Each had lived with his/her parents until their marriage. Harry never did live far from his family, as his house at 300 Cambria was next door to his parents at 284 Cambria. In fact, when Harry retired in 1949, two of his brothers and one sister were still living next door in the family home.

Harry was an extremely active and prominent citizen. He was the first chairman of the Stratford Board of Education and served the board for most of 25 years. Harry was also a chairman of the Perth-Stratford Advisory Board of the C.N.I.B. and president of the Stratford Rotary Club. He was warden and Sunday school superintendant of St. James Church. Harry was active in the Stratford Masonic Lodge and the Stratford Conservative Association.

Because of his prominence in the community, Harry’s obituary appeared on the front page of the newspaper when he died on June 16, 1949.  Janet continued living at 300 Cambria until at least 1960. She died in November 1970. She and Harry had three daughters: Margaret Jane, Jean MacCreadie, and Mary Elizabeth. There were six grandchildren at the time of Janet’s death.