Easter is the first Sunday after the first fourteenth day of the moon (the Paschal Full Moon) that is on or after March 21 (the ecclesiastical vernal equinox).
Easter has not fallen on the earliest of the 35 possible dates, March 22, since 1818, and will not do so again until 2285. It will, however, fall on March 23 in 2008, but will not do so again until 2160. Easter last fell on the latest possible date, April 25, in 1943 and will next fall on that date in 2038. However, it will fall on April 24, just one day before this latest possible date, in 2011.