In 1866 the first attempt in the US at a union for workers was called the?

In 1866, the first attempt at a union for workers in the United States was called the National Labor Union (NLU). It aimed to unite various labor organizations to advocate for workers' rights, including better working conditions and the eight-hour workday. Although it achieved some initial successes, the NLU eventually declined due to internal conflicts and the challenges of unifying diverse labor interests.