It was built in 1897 as the main post office for what was then the independent city of Allegheny and later became part of Pittsburgh.

After the post office closed in 1967, the building was slated for demolition as part of the Allegheny Center urban renewal project.

However, the Pittsburgh History and Landmarks Foundation (PHLF) mounted a successful campaign to save the building, raising about $835,000 to purchase and restore it for their own use.

In 1972, the building reopened as the Pittsburgh History and Landmarks Museum, exhibiting items from PHLF's collections of historic artifacts.

[4] In 1983, the lower level of the building became the first home of the Children's Museum of Pittsburgh.