Eolia was one of seven Harkness residences. The Roman Renaissance Revival-style mansion has 42 rooms. Designed by the New York architectural firm of Lord and Hewett, the mansion was built in 1906 by William and Jesse Stillman, sister of Mary Stillman Harkness.
Named "Eolia" after Aeolus, god of the winds in Greek mythology, the estate was purchased by Mr. & Mrs. Harkness in 1907. Architect James Gamble Rogers, known for his work at Yale University, designed the interior renovations, the pergola, and the carriage house. Rogers converted the interior of the mansion to "neoclassical style." The new color palette chosen to adorn the renovated residence was in keeping with Mary Harkness's expressed desire to "evoke the feeling of the inside of an oyster shell."
During the 1980's, a hurricane tore off the mansion's copper roof; consequently Eolia was boarded up and access denied to the public. From 1993 until the completed restoration in spring 1998, the mansion was open one time annually, on Harkness Family Day.