The roots of International Women's Day (March 8th) go all the way back to New York City in 1909 and the Socialist Party of America. However, from what I have learned the International Women's Day is today little known or celebrated in the US (correct me if I'm wrong).
The same goes to International Worker's Day, or May Day (May 1), which goes back to 1885 and the American Federation of Labor (AFL) fighting for the 8-hour work day.
I've heard this may have something with their socialist roots because Russia (USSR) is the country championed these two holidays.
I am sure International Children's Day (June 1) is the case because it is celebrated on June 1 in most Communist and post-Communist countries even though it seemed to first started in US too.
Is this the case for International Women's Day, and is the status of International Worker's Day (May Day) in the US related?