Women are not as well represented in government records as men. Plain and simple. This has to do with how women have been restricted by the law. The most obvious example of this is the right to vote.
While women didn't have the federal right to vote until the passage of the 19th amendment, some states did allow women to vote in local or even state elections. Googling can help you find when the state your female ancestor lived in granted suffrage or you can refer to this Wikipedia page.
Voter registrations don't provide a lot of information about her life. Maybe an address, occupation, and political party affiliation. But, like the census, it does place her in a specific location and time. Thus helping you to flesh out a timeline of her life.
Not all voting registers or lists are extant. I was unsuccessful in my search for early Utah voting records where women could vote in 1870. These records don't appear to exist anymore, leaving us with no records of those early women voters.
Additionally, if she fought for women's right to vote you may find her name mentioned in archival records for suffrage groups or even later, after the passage of the 19th amendment, as a member of the League of Women Voters. Archival records can be found in archival catalogs for individual repositories as well as catalogs like ArchiveGrid. Newspapers may also be beneficial since they report on membership group meetings and may include names of officers and others involved in the group.
Voter registrations can be found through websites like Ancestry.com and FamilySearch. Findmypast has unveiled a suffragette collection as well. Also look at a state archive or library for the possibility of records.
Take some time this month and locate your female ancestors in voting records.
Library of Congress - League of Women Voters Records
WorldCat - Women's Suffrage search
GenealogyBank Blog - African American Women- The Alpha Suffrage Club
GenealogyBank Blog - Women's Suffrage: The 19th Amendment Ratified This Day
Gena's Genealogy - Women's History Month 2015: Women's Suffrage