My Family Tree

William's official biography says that he was the son of WH Dennis and Mary Ann Sharpe, but he was not with that family in the 1881 census - they had another son William, age 6. Rather, WH is with the family of Thomas and Anne Eliza (Sharp) Dennis, age 16. He was named as a son in Thomas' obituary.

DENNIS, WILLIAM HENRY, carriage builder, trader, and farmer; b. ca. 20 January 1864 in Port Hill, son of William Henry Dennis, Sr., and Mary Anne Sharpe; m. 14 March 1885 Mary Ann Ellis, and they had seven children, Melbourne, Thomas C., Iva [Eva?], Milton W., Dana G., Robert C., and J. G.; Presbyterian; d. 15 July 1946 in O’Leary.
Dennis, a Liberal, was first elected to the Legislative Assembly in the general election of 1915 for 2nd Prince. He was re-elected in the general elections of 1919, 1923, 1927, 1931, 1935, 1939, and 1943. He was appointed Minister of Agriculture on 14 January 1936 and served in that ministry until 1943. Dennis believed in working alongside neighbours and members of the community to help them help themselves.
Dennis was educated in the local school. For the most part he worked as a carriage builder, but also traded in agricultural machinery, horses, buggies, wagons, and a variety of other items. Dennis, who did some farming, stayed in close contact with farmers all his life because of his involvement in trading and carriage-building. William Dennis died 15 July 1946. Mary Dennis, the daughter of John and Margaret Ellis, was born 24 November 1864 and died in 1953.

References: CPG 1920, 1940, 1945; Maritime Advocate and Busy East. 31(8) March 1941; Patriot 16 July 1946; PARO: RG Marriage License Vital Statistics Box M, 1884; MNI-Census 1891; Census 1901; O'Leary United Church Records; Bloomfield United Church Cemetery Records.

from Prince Edward Island Legislative Documents Online

History of Port Hill says that William Henry was the grandson of William and Mary Ann, and was the son of Thomas and Eliza (Sharp) Dennis.