Four lots on the corner of Chartres Street and Ursulines Avenue were sold by the Ursuline nuns in 1825 to Joseph LeCarpentier. The house, built in 1826, was designed by architect François Correjolles. In 1833, John A. Merle, Consul of Switzerland, purchased the home and designed and built the parterre garden. The next owners, Josephine Laveau Trudeau and her daughter, continued to improve the garden, though after subdividing and selling that portion of the property in 1865, the garden was replaced by commercial and industrial use until almost a century later.
Novelist Frances Parkinson Keyes and architects Richard Koch and Samuel Wilson, Jr., restored the Beauregard-Keyes House, its rear courtyard, and formal side garden. Completed in 1945, the rear courtyard is composed of a flagstone patio bordered by planting beds, with a central fountain. The fountain, a Victorian cast-iron model with an egret motif base, was secured and moved by Keyes from the yard of a tourist home in Vermont. In 1954, work on the side garden began, based on the original plans for the garden as constructed by the Merle family. This included a formal parterre garden with magnolias and sculpted boxwoods, and a cast-iron fountain at its center. Bricks from buildings previously on-site were salvaged to construct the garden’s walls. Iron gates and grilles were fabricated to allow pedestrians to view the garden. The estate is located within the Vieux Carré Historic District and was listed in the National Register of Historic Places in 1975.