"Two hundred seventy-seven women have been elected or appointed to the U.S. Congress. Jeannette Rankin (R-MT) has the distinction of being the first woman elected to serve in Congress. On November 9, 1916, she was elected to the House of Representatives as Montana's Representative-at-Large to the 65th Congress (1917-1919). Since Rankin's election, 276 additional women have served in Congress. These 277 women include 177 Democrats and 100 Republicans. Two hundred thirty-eight (152 Democrats, 86 Republicans) have served only in the House of Representatives; 31 (19 Democrats, 12 Republicans) have served only in the Senate; and eight (6 Democrats, 2 Republicans) have served in both houses. Of those in the House, four (3 Democrats, 1 Republican) have been Delegates to Congress. Ninety-three women serve in the 112th Congress: 76 in the House (52 Democrats and 24 Republicans) and 17 in the Senate (12 Democrats and 5 Republicans). Three of the women who serve in the House are Delegates, representing the District of Columbia, Guam, and the U.S. Virgin Islands; all are Democrats. Excluding Delegates, women currently hold 73 (16.8%) seats in the House of Representatives and 17 (17%) seats in the Senate, totaling 90 (16.8%) of the 535 voting seats in the 112th Congress. Including Delegates, women currently hold 76 seats in the House of Representatives, and 17 in the Senate, totaling 93 seats (17.2%) in the entire Congress."
CRS Report for Congress, RL30261