The federal Fair Labor Standards Act (FLSA) establishes basic standards for employment in the United States, addressing issues such as the minimum wage, payment for overtime, and child labor.
The FLSA applies to employers who: (1) are engaged in interstate commerce and have a gross volume of sales of $500,000 or more per year; or (2) who employ employees who are engaged in interstate commerce.  See 29 U.S.C. § 203(s)(1).  Because the level of involvement required for an employer or employee to be engaged in interstate commerce is relatively low, the vast majority of employers are subject to the federal FLSA.
Minnesota has a state version of the Fair Labor Standards Act, which imposes requirements on employers that are similar to those imposed by the federal FLSA.  See Minn. Stat. § 177.21 et seq.