The American woman suffrage movement remade the U.S. Constitution and effected the broadest expansion of voting eligibility in the nation's history. Yet it did more than change laws and citizenship. It also plausibly shaped participatory patterns before and after the winning of voting rights for women. Drawing upon the idea of formative practice and reporting on a range of historical materials—including an original data set of 2,157 petitions sent to the U.S. Congress from 1874 to 1920 concerning women's voting rights—we focus on woman suffrage petitioning as both presaging the practice of voting and, in a sense, preparing tens of thousands of women for that activity. Our analyses reveal that, before 1920, suffrage petitioning activity was heightened in general and midterm election years (especially among Republican-leaning constituencies), suffrage petitioning both enabled and reflected organization in critical western states, and that post-suffrage women's turnout was immediately and significantly higher in states with greater pre-suffrage petitioning (controlling for a range of political, organizational, and demographic variables). In its claims, symbolism, habits, and temporality, suffrage petitioning differed from other petitioning in American political development and marked a formative practice for women on their way to voting.