It all began with one single day in 1908 in New York City when thousands of women united and marched for better labor laws, conditions, and the right to vote. A year later on February 28, in a gathering organized by members of the Socialist Party, suffragists and socialists gathered again in Manhattan for what they called the first International Woman's Day.
The idea swiftly caught on and made its way to Europe. And in March of 1910, according to the BBC, German socialist Clara Zetkin introduced the concept at the International Conference of Women in Copenhagen. The 100 women in attendance, representing 17 countries, all agreed. International Women's Day was then formally honored on March 8, 1911 by Germany, Austria, Denmark, and Switzerland. Russian feminists also had a strong influence on the beginnings of the Russian Revolution, with Communist leader Vladimir Lenin making Women's Day a Soviet Holiday in 1917. Continue reading from Oprah Daily
The actual celebration of Women’s History Month grew out of a weeklong celebration of women’s contributions to culture, history and society organized by the school district of Sonoma, California, in 1978. Presentations were given at dozens of schools, hundreds of students participated in a “Real Woman” essay contest and a parade was held in downtown Santa Rosa.
A few years later, the idea had caught on within communities, school districts and organizations across the country. In 1980, President Jimmy Carter issued the first presidential proclamation declaring the week of March 8 as National Women’s History Week. The U.S. Congress followed suit the next year, passing a resolution establishing a national celebration. Six years later, the National Women’s History Project successfully petitioned Congress to expand the event to the entire month of March. Continue reading from History Channel
Women's History Month: How It Started and Why We Celebrate in March (People)
National Women’s History Month (Encyclopedia Britannica)
Why Women's History Month is in March (CNN)
Women’s History Month Statistics (US Census)
Why We Celebrate Women's History Month (ThoughtCo)