William Peter Ohlhauser is the son of William Leonard Ohlhauser and Elizabeth Herweh. He was born on March 5, 1879 in Ohio. He married Matilda Margaret Dornette on October 25, 1900.

Matilda Margaret Dornette is the daughter of John Frederick Dornette and Barbara Anna Scherzer. She was born December 25, 1875 and died May 25, 1944 in Cincinnati, Ohio. Her father was born in Hanover, Germany. Her mother was born in Bavaria, Germany. Together they raised 5 children: Elizabeth Ann, Lillian M., John William, Ralph O., and Edith.

According to the 1930 census the family resided on Harrison Ave. William and his son John William were meat cutters.