National Rosie the Riveter Day is observed in the United States every March 21 to celebrate the contributions of women who filled labor gaps during World War II. The day honors the millions of women who took on roles traditionally held by men, working in factories and shipyards to support the military effort. The term "Rosie the Riveter" originated from a song in 1942 and became a symbol of female empowerment, particularly through J. Howard Miller’s “We Can Do It!” poster, which was rediscovered in the 1980s and associated with the feminist movement. Although the day was first proclaimed by the U.S. Senate in 2017, it has not been consistently observed, with some institutions choosing to celebrate it in May or June. Despite not being a national holiday, the observance highlights a significant shift in women's roles in the workforce and the beginnings of a new era for American feminism and gender equality.