Merchant Street Historic District, Commercial district in downtown Honolulu, United States.

Merchant Street Historic District runs from Fort Street to Nuʻuanu Avenue in downtown Honolulu, where low brick and stone buildings from the 1850s to the 1930s stand among concrete high rises. Its styles range from plain 19th-century commercial to Richardsonian Romanesque, Italianate and Mission Revival. The Melchers Building at 51 Merchant Street dates from 1854, and the Kamehameha V Post Office of 1871 was Hawaiʻi's first building of precast concrete blocks reinforced with iron bars.

The district emerged as a center of trade and finance during Honolulu's development in the 1800s. It was listed in the National Register of Historic Places in 1973, recognizing its role as the financial backbone of the Hawaiian islands.

The Yokohama Specie Bank branch, built in 1909, served Japanese-, Chinese- and English-speaking customers in separate areas, and its interior holds paintings by a local artist. The T.R. Foster and Royal Saloon buildings, both Italianate brick, now house O'Toole's Irish Pub and Murphy's Bar & Grill. The district borders Chinatown to the north.

The district is easily walkable and exploreable since the buildings sit close together in a compact arrangement. Visitors should wear comfortable shoes and allow time for strolling and observing the details across the structures.

The Yokohama Specie Bank branch at 36 Merchant Street, built in 1909, handled Japanese-, Chinese- and English-speaking customers in separate areas. After Pearl Harbor it was seized by the Alien Property Custodian; the ground floor stored confiscated possessions and the basement held up to 250 military detainees. Former customers recovered their deposits only years later, with interest paid from the 1960s.