In 1870, Coggeshall became a charter member and secretary of Iowa's Polk County Woman Suffrage Society and was later (1898) president of the Des Moines Equal Suffrage Club. Her most influential suffrage activity, however, stemmed from her involvement with the Iowa Woman Suffrage Association (IWSA), of which she was a charter member. She served as its president (1890, 1891, 1903–05) and then as honorary president (1905–11). In the latter capacity, she marched in America's third-ever women's suffrage parade, which took place in Boone, Iowa, in 1908. Coggeshall was the first editor (1886–88) of the IWSA's monthly ''Woman's Standard'', Iowa's main suffrage newspaper, founded by
Martha Callanan. She returned to edit the paper again in 1911. She frequently wrote for the paper after her first editorship ended, as well as for national newspapers. In 1895, Coggeshall was elected to the board of the
National American Woman Suffrage Association (NAWSA), becoming the first woman from west of the Mississippi River to join the NAWSA board and the only one of the early Iowa suffragists to be active at the national level. She spoke at the NAWSA national conventions in 1904 and 1907. Coggeshall not only lectured and wrote on suffrage, she got involved in a major lawsuit. In 1894, the state of Iowa had passed a law allowing women to vote in city bond elections. In 1908, when the city of Des Moines defied this law and denied women ballots in just such an election, Coggeshall brought a lawsuit against the city. The Iowa Supreme Court held that the election was void because women, as a class were barred from voting. Coggeshall died of pneumonia on December 22, 1911. Although she did not live to see American women get the vote, fellow suffragist
Carrie Chapman Catt dubbed her "the mother of woman suffrage in Iowa". ==Legacy==