December 1, 1990
As part of the Civil Justice Reform Act of 1990, designed to address the problems of cost and delay in the federal courts, Congress created 11 new circuit judgeships, 61 new district judgeships, and 13 temporary district judgeships (providing that the first vacancy on the court in question occurring more than five years from the date of the act would not be filled). The 1990 act was the last major expansion of federal court judgeships.
View the timeline: The Structure of the Federal Courts