Women’s History Month celebrates the often-overlooked contributions of women in history, society, and culture. It has been annually observed in the United States and other countries, including the United Kingdom and Australia, every March since 1987. The month is observed in October in Canada. March is selected as the month for observing Women’s History Month to correspond with International Women’s Day on March 8, and Canada observes it in October in correspondence with Persons Day on October 18.
The month-long commemoration started with Women’s History Day in 1978, organized by the school district of Sonoma, California. Hundreds of students participated in the essay competitions, many presentations were given, and a parade was held in Santa Rosa. The idea caught on and, a few years later, school districts, communities, and organizations all over the country were celebrating the day. In 1980, the National Women’s History Alliance championed for the holiday to be observed as a national week, and this was backed by President Jimmy Carter, who issued the first proclamation declaring the week of March 8 as National Women’s History Week. The following year, Congress forwarded a resolution establishing a national observance. Six years later, the expansion of the event to the whole month of March was successfully petitioned by the National Women’s History Project. (Source)