The mansion, organized as the Trabzon Museum (Kostaki Mansion), was built as a residence by Banker Kostaki Teophylaktos in the early 1900s (1898-1913) on Zeytinlik Street. It is known that the architects of the mansion were Italian and many of the materials used in the building were brought from Italy. When Kostaki Teophylaktos went bankrupt in 1917, this building and all its assets were seized and the mansion was purchased by the Nemlioğlu Family. During his first visit to Trabzon on 15-17 September 1924, the great leader Atatürk, along with his wife Latife Hanım and her accompanying delegation, were hosted in this mansion.

During the time of Trabzon Governor Ali Galip Bey, it was expropriated for 25,000 TL between 1927-1932 and was used as the Government Mansion between 1927-1931 and as the inspectorate building between 1931-1937. All floor walls of the mansion, which is among the few examples of civil architecture in our country, except the basement floor, are completely decorated with hand-carved ornaments. The mansion, whose restoration was completed by the Ministry of Culture and Tourism between 1988 and 2001, was opened to visitors as the Trabzon Museum on April 22, 2001. The basement of the mansion is organized as the Archaeological Works Section, the ground floor is the Mansion Exhibition, the first floor is the Ethnographic Works section and the mezzanine floor is the Administrative Section.