She rose to be corresponding secretary of the National American Woman Suffrage Association and played a key role in organizing meetings across the country.

[2][5] After J. Heron Foster's death in 1868, Rachel, her sister Julia, and her mother moved to Philadelphia, where they joined the Citizens' Suffrage Association.

[2] When but 19 years of age, Avery and her elder sister, Julia Foster, were appointed vice-presidents for Pennsylvania of the National Woman Suffrage Association.

[2][5] In February 1888, Foster organized the International Council of Women[3] in Washington, D. C., held under the auspices of the National Woman Suffrage Association.

[2] On November 8, 1888, Foster married Cyrus Miller Avery (1854–1919), whom she had met when he was a delegate to the International Council of Women meeting earlier the same year.