aka NGC 2099 is the brightest and richest open cluster in the constellation Auriga.
It was discovered by the Italian astronomer Giovanni Battista Hodierna before 1654.
M37 was missed by French astronomer Guillaume Le Gentil when he rediscovered M36 and M38 in 1749.
French astronomer Charles Messier independently rediscovered M37 in September 1764 but all three of these clusters were recorded by Hodierna.

M37 exists in the antipodal direction, opposite from the Galactic Center as seen from Earth, so is in one of the nearby outer arms. Specifically it is still close enough to be in our own.
Estimates of its age range from 347 million to 550 million years. It has 1,500 times the mass of the Sun (M☉) and contains over 500 identified stars, with roughly 150 stars brighter than magnitude 12.5.

At its estimated distance of around 4,500 light-years, the cluster's angular diameter of 24 arcminutes corresponds to a physical extent of about 20–25 ly.