Armatage was the first woman elected to the park board—and was the only woman on the board for her entire length of service. Armatage was elected to the park board in 1921 in the first general election in which women had the right to vote. She was vice president of the board from 1924 to 1927. She chaired the Privileges and Entertainment Committee in her early years on the park board and when a combined Playground and Entertainment Committee was created in 1928 she chaired that committee until her retirement from the board in 1951.

One of Armatage’s first special assignments as a park commissioner, perhaps reflecting stereotypes of women at the time, was to be responsible for the “artistic selection and arrangement of furnishings at The Chalet,” as noted in the park board’s 1923 annual report. The Chalet was the new golf clubhouse and shelter built at Glenwood (Wirth) Park. Armatage and her uncle, F. A. Dunsmoor, both contributed to the furnishings of the clubhouse.

Armatage was especially active in promoting cooperation between the school board and park board to avoid duplication of facilities and get the most out of spending by both boards. When the park boards and school boards were first considering cooperative development of facilities in the southernmost portion of the city after its annexation from Richfield in 1926, Armatage visited Detroit on behalf of the park board to view the results of cooperative efforts there. When the possibility of developing joint facilities was renewed after nearly two decades of depression and war, Armatage sponsored a joint resolution between the park board and school board in 1948 that led directly to cooperative development of Waite, Armatage, Kenny and Cleveland parks and schools.

Armatage lived near Lake Harriet in a nine-family community called the “Colony.” According to research by Tom Balcom, nine families built homes on land given to them in 1893 by Charles Loring in the 4600 block of Fremont Avenue in the hopes that initial development would lead to more families wanting to build homes in the area.

In addition to her work on the park board, Armatage was a local leader of Campfire Girls and was on the national board of directors of that organization.

Upon her retirement in 1951 at the age of 81, the park board passed a resolution honoring Armatage’s service on the board, noting that “it is to her, more than to any other person, that the people of the City of Minneapolis owe a debt of gratitude for the promotion of the integrated school and park idea.” The 1951 annual report also noted that she had “championed many activities and diversions for the recreation of youth which are commonplace in the recreation program of today.”