As a claim of discrimination under the federal statute is an attempt to remedy a personal injury to civil rights, the appropriate statute of limitations is taken from the appropriate state's personal injury tort law.
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Not written by a barrister. The name was thought up by a second-year American law student sitting in a coffeehouse in Manhattan. Neither an authoritative statement of the law nor legal advice.
Don't rely. Quick work.