In addition to the mansion, it includes a carriage house, greenhouse, gardener's residence, and a Russian-style dacha added by Ambassador and Mrs. Davies.

The mansion sits at the highest point of the grounds and provides views of the city to the south and the affluent Cleveland Park suburb to the north.

[5] The property, originally part of a larger estate, "Twin Oaks", was bought in 1888 by Gardiner Greene Hubbard, founder of the National Geographic Society, and named "The Causeway".

His daughter Mabel married Alexander Graham Bell and inherited the property, which she sold to James Parmelee, a Cleveland financier.

In 2006, an agreement was reached whereby 13 acres (53,000 m2) of the estate are to be conserved as open green space and managed by Tregaron Conservatory.

[8] A farmhouse dating back to 1890 sits at the edge of the estate and was converted to office space for the International School.