In addition to designing schools and private homes in Connecticut and New York, Theodate designed and supervised the reconstruction of President Theodore Roosevelt's Birthplace in New York City.
According to writer and critic Brendan Gill, Theodate Pope Riddle was one of the ten most distinguished American women of the 20th century. Her friend, famed psychologist Carl Jung, saw her as an intuitive woman who trusted her instincts, ignored raised eyebrows, and courageously forged ahead despite the restrictions of her day.
While Westover School was being constructed on the Middlebury Green a century ago, the School's Founder and First Headmistress, Mary Hillard, visited the building site one moonlit night with her good friend Theodate Pope Riddle, who was the architect for the new School. As they gazed at the sheer size of the project, Mary grew momentarily alarmed at the daunting endeavor she had undertaken. At seeing Mary's unease, Theodate told her good friend, Be still and let your spirit fill the buildings.
Theodate's own spirit still fills the Hill-Stead Museum in Farmington, CT, more than 100 years after she designed it as a country estate for her parents - her first of a number of major architectural achievements.
Hill-Stead has been a hub of activity ever since the Pope family first occupied their newly built country estate. Here, from 1901 to 1946, in succession, Alfred and Ada Pope and their daughter Theodate, with her career-diplomat husband John Wallace Riddle, entertained many illustrious individuals - authors, artists, poets, academics, and presidents.