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Assay Office Museum
Assay office museum

James F. Bailey Assay Office Museum

The Assay Office Museum contains many tools and implements used in the assaying process, as well as furniture and artwork owned by the Bailey family.

At the turn of the twentieth century, hard rock mining in Boulder County was in full swing, and the area known as Wall Street played a prominent role in this chapter of our community’s history. The assay office was the place where prospectors would take their ore samples to find out whether or not they had potentially “struck it rich.” So important was the determination of the assayer that the results of their work could, and often did, make or break a prospector.


May through October
3rd Saturday: 11 a.m. – 3 p.m.

Show Calendar

Admission & Tours

  • Admission is FREE
  • Tours for groups of 12 or more people are available by appointment mid-April through mid-October.

Getting There

The Assay Office is located west of Boulder in Fourmile Canyon

6352 Fourmile Canyon Dr
Boulder, CO 80302

360 Tour

Learn More About Hard Rock Mining

Hard Rock Mining Virtual Tour

Hard Rock Mining Tour

Take a virtual tour of Boulder County’s mining history. A map shows locations and information about the prominent mines of this area. The Switzerland Trail Railroad also gets special attention for its role in the mining industry and life in Boulder County in general.

Nederland Mining Museum

Nederland Mining Museum
Visit the Nederland Mining Museum and get a glimpse into the world of hard rock mining days in Boulder County during the late 19th and early 20th centuries. Learn about the lives of the miners of yesteryear.

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