Williams v. Illinois, 399 U.S. 235 (1970), was a United States Supreme Court case in which the Court held that, if a person cannot afford to pay a fine, it violates the Equal Protection Clause to convert that unpaid fine into jail time to extend a person's incarceration beyond a statutory maximum length.
The syllabus of the case stated:
A companion case, Morris v. Schoonfield, was "remanded for reconsideration in light of intervening Maryland legislation and decision in Williams".