Presidential Regional Primaries Act - Establishes five regional Presidential primary election districts and sets dates for primary elections to be held in such districts for the purpose of electing delegates to the national political conventions. Prohibits any State from conducting a Presidential primary election except in accordance with this Act. Directs the Federal Election Commission to reimburse each State which held a Presidential primary in 1976. Directs such Commission to report to the Congress and the President on the steps it has taken to carry out such regional primary system.