Nancy Pelosi may be poised to be the first woman to serve as speaker of the House, but she follows in an interesting line of women. The first woman elected to Congress was Republican Jeannette Pickering Rankin of Montana in 1917. Rankin also holds the distinction of being the only legislator of either sex to vote against the United States' entering both World War I and World War II. In 1932, Democrat Hattie Caraway of Arkansas became the first woman elected to the Senate, winning a special election to complete the vacancy caused by the death of her husband, Sen. Thaddeus H. Caraway. Known as "Silent Hattie," she once remarked that the reason she never spoke on the Senate floor was that "the men have left nothing unsaid."

Sources:

Biographical Directory of the United States Congress 1774–Present

The American Congress: The Building of Democracy, Julian E. Zelizer, Editor; Houghton Mifflin Co., 2004