Two years after designing the elegant Napton and Leonard apartments on Granite Street, architect William O’Brien designed this building for widow Mary O’Rourke in 1908. O’Brien, whose clients ranked among Butte’s wealthiest, designed the O’Rourke as a detached addition to the older Merrimac House apartments behind it. The Merrimac, built at the rear of this lot for John and Mary O’Rourke in 1892, was originally attached to their home. John O’Rourke was one of the few Virginia City miners who made substantial money in placer mining. He wisely invested his profits in Butte real estate, wholesale liquor, and a boot and shoe store. After his death in 1907, Mary had contractors remove the O’Rourke home, build the new O’Rourke building, and add bay windows and grand stone embellishments to the Merrimac, stylistically marrying the two buildings. The resulting Eclectic style buildings provided sophisticated quarters for teachers, machinists, and clerks, and also for Mary and her daughter, Marie. They managed the sizeable O’Rourke estate until Mary’s death in 1949. Marie lived in Unit E and managed the substantial estate until 1979.