First States to Grant Women Suffrage
In the wake of the Civil War, however, reformers sought to avoid marginalization as “social issues” zealots by focusing their message exclusively on the right to vote. The first state to grant women complete voting rights was Wyoming in 1869. Three other western states—Colorado (1893), Utah (1896), and Idaho (1896)—followed shortly after NAWSA was founded. But before 1910 only these four states allowed women to vote. “Why the West first?” remains a contested question. Some scholars suggest that the West proved to be more progressive in extending the vote to women, in part, because there were so few of them on the frontier. Granting women political rights was intended to bring more women westward and to boost the population. Others suggest that women had long played nontraditional roles on the hardscrabble frontier and were accorded a more equal status by men. Still others find that political expediency by territorial officials played a role. They do, however, agree that western women also organized themselves effectively to win the right.
https://history.house.gov/Exhibitions-and-Publications/WIC/Historical-Essays/No-Lady/Womens-Rights/