Cairnwood Estate was designed by Carrère and Hastings in the Beaux Arts style. The meticulous decorative elements blend influences from classical Greek and Roman architecture with French Renaissance ideas. The exterior of Cairnwood shows a mixture of rustic elements and high style. The overall effect is that of a majestic French chateau adapted to the conditions and requirements of American life during the Gilded Age.
The estate consists of a main house, adjacent courtyard, garden house, and formal gardens. Just a few feet from Huntingdon Pike are the entrance gate and carriage house. In 1895, a stable, greenhouses, a pergola, three terraced gardens and access to many acres of farmland, surrounded by woodlands, completed the idyllic country home.