Herein I summarize what is known about Cockerell's bumblebee, Bombus cockerelli Franklin, a New Mexican bumblebee species whose existence has been largely overlooked for decades because of a combination of rarity, geographic restriction, and taxonomic confusion. It is noteworthy that the known distribution covers only about 777 km², giving it the smallest known range of any bumblebee in the world. There are 34 known specimens, and I present historical details regarding their collection (dates, places, and host plants), deposition, and identification; hopefully, this information will allow others to locate additional specimens of this species. It is further notable that most of the known specimens are late-season queens, and males remain unknown, suggesting that the species may nest and forage in areas of dense forest.