The correct name for this trail is "Red Mailbox". Note this is singular, not plural "mailboxes" as it's commonly called.

It is named after a single large red mailbox at 2161 Empire Grade, which marks a private driveway that leads down to the original entrance to this mountain biking trail. A friend of mine who lived in the house informed me that in the mid-2000s, the mailbox was painted white with flowers on it to dissuade mountain bikers from trafficking the private road. This mailbox is still there today, white and flowery, and you can still get to the trail this way, but in mid 2000's, trail pixies created an alternate (and much more popular) entrance a mile or so up the road at Twin Gates.

In most cases, you can't say definitively what a MTB trail's name should be. This trail is unique in that its name is actually a marker to identify the trail. As such, please consider renaming this trail to its correct name, "Red Mailbox".