"Federal law does not require employers provide employees with either paid or unpaid vacation leave. Both the Fair Labor Standards Act (FLSA) and the Department of Labor have left the matter of vacation leave to the States to develop applicable laws.
Vacation Leave and State Law
There are no States that require employers to provide employees with either paid or unpaid vacation leave. However, states vary considerably on the requirements placed on employers if they choose to provide vacation benefits. Vacation Leave Law Summaries"