Many websites dedicated to women's history exist and are freely available. Below find a small selection of sites focused on suffrage and the history of women's voting rights.
National Archives: Women’s Rights
Library of Congress: Women's History and Suffrage
National Women’s History Museum
National Park Service:
Radcliffe Institute for Advanced Study: Schlesinger Library on the History of Women in America
Kansas Historical Society: Women's Suffrage Collections
Turning Point Suffragettes Memorial Association: Suffragettes in Kansas