According to brittanica.com, “International Women’s Day was first conceived at the Second International Socialist Women’s Conference in 1910. Its leaders, notably German activist Clara Zetkin, wanted to mobilize working women in a setting apart from the mainstream feminist movement, which they felt overlooked working women.

By the 1970s American feminist groups extended the now-mainstream International Women’s Day to Women’s History Week, an effort to amplify women’s history in schools. In 1975 the United Nations moved to formally sponsor an annual celebration of International Women’s Day. The force behind the movement made itself irresistible, and, as more and more groups began celebrating the full week—as well as lobbying for it to be nationally recognized—President Jimmy Carter designated the first National Women’s History Week, the week including March 8, in 1980.

Women’s history observations snowballed from there. By 1986, 14 states recognized March as Women’s History Month, and the next year the U.S. Congress established Women’s History Month as an annual federally recognized observance. Each sitting U.S. president since 1995 has issued a yearly proclamation honoring the role of American women in history.”