Situated on Pitt Street, McKellar House was designed by John Arthur Burnside (1856-1920) and built by J.C. White in 1895 as a residence and consulting rooms for Dr Thomas George McKellar (1865-1952). The building is of architectural and historical significance and forms a prominent position near the corner of George and Pitt Streets opposite Knox Church. One of its more striking features is the turret with the slate roof.

Both iwi history and archaeological evidence show Māori occupation in the Ōtākou / Otago region since the 12th century. Today, Kāi Tahu mana whenua is recognised over a large part of Te Wai Pounamu. Kāti Māmoe and Waitaha shared occupation are always acknowledged. The hapū Kai Te Pahi, Kāti Moki, and Kāti Taoka still maintain their presence and responsibility as kaitiaki in this region. While there were no permanent settlements around George Street, the area near the Toitū Tauraka waka (List No. 9774) south at the current exchange, was known as Ōtepoti.

Pitt Street had a long association with medical professionals which began in 1849 when Dr William Purdie bought a house near the bottom of the street which had been built for, but rejected by, the leader of the Otago settlement scheme, Captain William Cargill. From the 1880s, several doctors chose the street for their substantial homes and surgeries, some of which are now student flats. Thomas McKellar's surgery was used until 1980, with Dr Oliver Chapman and Dr William Brown among the last tenants.
Thomas McKellar had returned from medical studies in Edinburgh in 1893 and set up practice when he purchased the Pitt Street property in 1896. The 18-room mansion has a slate roof with brick walls with Oamaru stone facings. Stained-glass sidelights flank the front door. The corner turret has a slate roof and curved windowpanes, unusual at the time the house was built in the late 1890s. On the ground floor, a curved glass door leads to a veranda with elegant cast-iron balustrades. Upstairs, a large octagonal skylight illuminates the spacious hallway and an archway painted to look like marble leads to two of the seven bedrooms. Three of the ground-floor rooms served as his waiting room, nurse's office, and General Practitioner’s surgery but a cubicle containing a sink is one of the few remaining signs of this.
The house was designed by J.A. Burnside who called for tenders for the ‘erection of a residence in Pitt Street’”. Apparently, Mr Burnside envisaged a very grand residence and showed the McKellar’s pictures of English and Scottish palaces, while the McKellar’s had something more modest in mind.

After being put up for sale in 1931 but not selling, the property was then divided into flats in 1939 with McKellar living in the bottom floor section while he let the top floor. In the 1930s the area above the portico over the pillared entrance was closed in to enlarge the room behind it. A wooden fire escape has been added to the upstairs back room of the house. The billiard room has been extended with a beamed lean-to roof over top of the ground floor lean-to scullery/kitchen area. It became the family home of Professor Peter McKellar, who inherited the house on his mother’s death in 1965. The house sold in 2016 after being in the McKellar family for 120 years. Today it is a student flat, which recently won the Best Flat Awards from Otago University Student’s Association in 2021. In December 2022 the land was subdivided.