Born in Colorado in 1880/1881 and a resident of Arizona beginning in 1904, Mrs. McKay (as she was known to her colleagues and in legislative records of the time) served 3 terms as a member in the Arizona House of Representatives. In those years, the Legislature customarily met in alternating years, and McKay represented Cochise County in 1917 and Gila County in 1919 and 1923.
Rosa McKay is best known for securing the passage of a minimum wage act for women. She introduced it for the first time as a new legislator in 1917. House Bill 3 provided that women must be paid a weekly wage of at least $10. It was signed into law by Governor Thomas E Campbell on March 8, 1917.
The enactment of the legislation was celebrated with sandwiches. As noted in the Journal of the House, p. 542 (pp. 1165-1166 of PDF):
The law was published in the Session Laws as Laws 1917, Chapter 38 (pp. 51-52) but was challenged and struck down.
Rosa McKay was undeterred. She introduced it again in 1919, revising the minimum wage to $20 per week. H. B. 5 failed in the House. She tried again in 1923. House Bill 36, setting a wage of $16 per week, was adopted and published as Laws 1923, Chapter 3 (pp. 6-7). Violations were punishable by a fine of not less than $50 or imprisonment in the county jail for not less than 10 days. However, in April 1923, the United State Supreme Court ruled that minimum wage laws were unconstitutional. Nevertheless, Rosa McKay was fondly remembered in Arizona, credited for the minimum wage law and other measures championing social issues.
In 1923 she was a candidate for Speaker of the House, but withdrew in favor of Dan Jones of Maricopa County “in the best interests of Democracy and the State of Arizona”. In addition, she served for 8 years on the Board of Visitors of Tempe Normal School (which later became Arizona State University), as a member of the Child Welfare Board, and as a delegate to the national convention in New York City. She was awarded an honorary membership of the Boy Scouts of America.
She died at age 53 in 1934. The state flag was lowered to half-staff in her honor.