https://en.wikipedia.org/wiki/Seventh_Amendment_to_the_Unite...
> In Suits at common law, where the value in controversy shall exceed twenty dollars, the right of trial by jury shall be preserved, and no fact tried by a jury, shall be otherwise re-examined in any Court of the United States, than according to the rules of the common law
47/50 states also provide for this right in their constitutions. the remaining three don't have it in their constitution but still have legislation or rules supporting it