Casimir Pulaski Day is a holiday celebrated in the United States, particularly in Illinois, to honor the contributions of Polish-American Revolutionary War hero Casimir Pulaski. He is known for his role in the American fight for independence and is often referred to as the "Father of the American Cavalry." The day is observed on the first Monday of March. The holiday was officially recognized in Illinois in 1977 and is marked by various events, including parades and educational activities. It serves to celebrate Polish heritage and the significant impact of Pulaski on American history.