She was born Nora Stanton Blatch in Basingstoke, Hampshire, England in 1883 to william Blatch and Harriot Eaton Stanton, daughter of Elizabeth Cady Stanton. She studied Latin and mathematics at the Horace Mann School in New York, beginning in 1897, returning to England in the summers. The family moved to the United States in 1902. Nora attended Cornell University, graduating in 1905 with a degree in civil engineering. She was Cornell University's first female engineering graduate. In the same year, she was accepted as a junior member of the American Society of Civil Engineers (ASCE), and began work for the New York City Board of Water Supply. She also worked for the American Bridge Company in 1905–06.
In 1908, she married the Inventor Lee de Forest, and helped to manage some of the companies he had founded to promote his invention and the new Technology of wireless (radio). The couple spent their honeymoon in Europe marketing radio equipment developed by de Forest. However, the couple separated only a year later, due largely to de Forest's insistence that Nora quit her profession and become a conventional housewife. Shortly afterward, in June 1909, Nora gave birth to their daughter, Harriot. In 1909, she began working as an Engineer for the Radley Steel Construction Company. She divorced de Forest in 1911. After her divorce, she continued her engineering career, working for the New York Public Service Commission as an assistant Engineer, and later for the Public Works Administration in Connecticut and Rhode Island as an Architect, engineering inspector and structural-steel designer.
Following the examples set by her mother and grandmother, Nora also became active in the growing women's suffrage movement. She was the first female member of the American Society of Civil Engineers, where she was allowed to be a junior member only and denied advancement to associate member in 1916 solely because of her gender. At the time, women were only admitted as junior members. In 1916, she sued the American Society of Civil Engineers (ASCE) for refusing to admit her as a full member, even though she met all requirements. Blatch lost, and no woman became a full ASCE member for a decade. In 2015, she was posthumously advanced to ASCE Fellow status.
Nora worked as a real-estate developer and political Activist until her death in Greenwich, Connecticut on January 18, 1971.
