The first woman elected to Congress was Jeannette Rankin of Montana in 1917. Rep. Nancy Pelosi became the first, and only, female Speaker of the House in 2007. The Senate has never had a female Majority Leader. And 17 states still have never elected a female Senator.
Progress for women has been slow in Congress, though that pace has quickened in the past few election cycles.
Read more about which states have moved forward in gender parity and which have not in this analysis in U.S. News and World Report.