Bedford College alumna, 1876
A supporter of women's rights she attended the Women's Suffrage Conference held in London in April 1871. Soon afterwards she joined the London Society for Women's Suffrage.
During this period she became friends with other suffragists such as Helen Taylor, Millicent Garrett, Elizabeth Garrett, Barbara Bodichon, Jessie Boucherett, Emily Davies, Francis Mary Buss, Dorothea Beale, Anne Clough, Elizabeth Wolstenholme-Elmy, Louisa Smith, Alice Westlake, Katherine Hare and Harriet Cook. She was the sister of fellow suffragist Jane Cobden, who was also an alumna of Bedford College.
Cobden-Sanderson worked for the Independent Labour Party and was arrested as a suffragette in October 1906. George Bernard Shaw wrote a letter of protest in September and she was released the following month. She was a founding member of the Women's Freedom League. She also helped form the Women's Tax Resistance League in 1909.
In 1907 she was invited to speak in the United States by Harriet Stanton Blatch to tell American suffragettes about the protest methods used in Britain. She addressed the first meeting of the Bryn Mawr College Suffrage Society using the title 'Why I went to Prison'.