M37 (NGC 2099) is the eastern-most star cluster of the three Messier objects found in Auriga.

The cluster lies between El Nath (beta Tau) and theta Aurigae. The naked eye is best for locating the general location. Starting at El Nath you'll note a star close-by, to its east. This is 136 Tauri (4.6). Now follow this star due north ten degrees and you'll encounter theta Auriga.

Putting theta at the top of your viewing field, M37 will be near the bottom, with M36 to the northwest: binoculars.

At perhaps 300 million years old, M37 is the oldest of the three Messier objects in Auriga. There are no blue luminous stars here, and yet the cluster has more stars than the others, perhaps as many as two hundred.