Like the original White House, the Halloran mansion is two stories and was initially built flat to the ground. It has two oval rooms (one, a parlor, on the main floor; the other upstairs as part of the master bedroom suite), a ballroom and other amenities. A portico added in 1820 greets visitors, an especially useful feature on cold or inclement days. Behind the mansion, a large red brick structure was used to house the servants. 

The first major renovation occurred in phases between 1898 and 1903, installing electricity and plumbing. By the late 1950s, age had caused serious wear on the mansion. Following the lead of President Harry S. Truman’s renovation of the White House, the mansion was essentially rebuilt from 1959 to 1962. This involved constructing a proper foundation and basement (which is now used for servants’ quarters), new heating, plumbing and the addition of air conditioning.  

While the main floor is very similar to the original design, the last renovation introduced two informal spaces: a family room (essentially a den) and a family dining room (in addition to the formal dining room). The kitchen was upgraded (as it would be again in 1996).  

The second floor is very different. The master suite, anchored by an oval parlor, has two bedrooms and two bathrooms. The number of bedrooms was reduced to five, each with a private bath and a small parlor (creating small suites). The nursery, located across from the master suite, was upgraded with better plumbing and an adjacent bedroom for a nanny. 

Guests to the Halloran mansion are regularly impressed with the wealth and elegant beauty of the Grand Vestibule, the Blue Room, Green Room and Grand Ballroom. The handsome, marble Grand Staircase connects the two floors