After the original Post Office was destroyed in the fire of 1865, Postmaster James Pinney built the current building in just 29 days in 1867. Pinney lived in one part of the building while he sold stamps, books, guns, knives, and other merchandise in the other half. The building also served as a library for those rare miners who read books.

Pinney resigned as postmaster of Idaho City in 1872 and from 1872-1910, it was still the post office, but also a meat market and where the "Idaho World" newspaper was published. In 1953, the old post office was deeded to Idaho City for $10, and the present-day museum was opened during the Gold Rush Days of in June 1958 and is run by the Idaho City Historical Foundation.

The museum was open on this Memorial Day, and the costumed guides were all over Idaho City because they were participating in a show that ran hourly at the outdoor theater on Main Street. Having our restless dogs with us didn't allow us a chance to visit the museum itself, but we enjoyed seeing the costumed guides around town and talking with some of them. Due to gunfire and Katie's aversion to loud noises, we had to pass on the show while we were there, but we heard it was really interesting.