From the U.S. Dept of Labor's website:
Labor Day, the first Monday in September, is a creation of the labor movement and is dedicated to the social and economic achievements of American workers. It constitutes a yearly national tribute to the contributions workers have made to the strength, prosperity, and well-being of our country.
The first Labor Day holiday was celebrated on Tuesday, September 5, 1882, in New York City, in accordance with the plans of the Central Labor Union. The Central Labor Union held its second Labor Day holiday just a year later, on September 5, 1883.
In 1884 the first Monday in September was selected as the holiday, as originally proposed, and the Central Labor Union urged similar organizations in other cities to follow the example of New York and celebrate a "workingmen's holiday" on that date. The idea spread with the growth of labor organizations, and in 1885 Labor Day was celebrated in many industrial centers of the country.
In a different definition of Labor Day weekend, in 1989, on that weekend, I exerted a specific form of labor. Our son was born. After a very long 22 hours of labor, he was born on September 2 at 11:48 AM. I remember it as clearly as if it happened yesterday, not 21 years ago. Natural childbirth will has that effect.
He is the joy of my life and I am a very proud mom.
Live long and prosper.