In association with several other local women, Hannah Barker formed the Boulder Creamery in 1887. Hannah Barker was appointed to the board of directors of Boulder Bank. In addition to her business endeavors, Barker was involved in numerous civic causes. Barker founded the Boulder Women's Club and was active in the Ladies' Literary Society and the Boulder Fortnightly Club. She was also active in supporting Boulder's Congregational Church and Columbia Cemetery and was a member of Boulder's Colorado Chautauqua Association. In 1911, Barker donated land to the City of Boulder at the corner of 15th and Spruce Streets for use as Barker Park. Barker was also active in a number of temperance movement causes.