How did women use petitions to mobilize politically during the period of no and limited suffrage? In this paper I analyze an original data set containing 279,898 petition signatures from Norwegian women in 1905. The signatures were collected to make up for women’s exclusion from the official referendum on independence from Sweden. By calculating the share of adult women who signed the petition in each of the 633 municipalities, I investigate the factors that allowed women to organize effectively, including urban networks, industrialization and low levels of income inequality. In addition, I explore how the mobilization subsequently paved the way for women’s electoral participation and entrance into municipal councils. The study will show how the mass mobilization of women was achieved, and its consequences for women’s political participation.