NASA says the full moon tonight is a Supermoon.
That is when the moon is full and closest to the earth at the same time.
"On Tuesday morning, at 2:31 AM EDT, the Moon will be at perigee, its closest to the Earth for this orbit," according to the space agency.
The moon has actually been almost a perfect circle in the sky for the last several days.
"The Moon will appear full for about 3 days centered on this time, from early Sunday morning into early Wednesday morning."
This moon is known by a number of names.
"Crow Moon, Crust Moon, Sap Moon, Sugar Moon, Worm Moon, Lenten Moon, the Holi Festival, Medin Poya, a Supermoon, and the Purim holiday."
NASA says the Maine Farmer's Almanac first published "Indian" names for the full Moons in the 1930's.
"As the full Moon in March and the last full Moon of winter, this Moon is called the Crow Moon, Crust Moon, Sap Moon, Sugar Moon, or Worm Moon. The more northern tribes of the northeastern United States knew this as the Crow Moon, when the cawing of crows signaled the end of winter. Other northern names were the Crust Moon, because the snow cover becomes crusted from thawing by day and freezing by night, or the Sap (or Sugar) Moon as this is the time for tapping maple trees.
The agencies website says that tribes more to the south called this the Worm Moon after the earthworm casts that appear as the ground thaws.
The Europeans called this the Lenten Moon, as this Moon corresponds with Lent, and the next full Moon, the first full Moon in Spring, occurs just before Easter.