It was discovered on 12 March 1871, by German astronomer Robert Luther at the Bilk Observatory in Düsseldorf, Germany.

[2] Amalthea is thought to be a fragment from the mantle of a Vesta-sized, 300–600 km diameter parent body that broke up around one billion years ago, with the other major remnant being 9 Metis.

[3] The spectrum of Amalthea reveals the presence of the mineral olivine, a relative rarity in the asteroid belt.

[4][5] Based on observations made during a stellar occultation by Amalthea of a 10th-magnitude star on 14 March 2017, it was announced in July 2017 that the asteroid has a small, 5-kilometer-sized satellite, provisionally designated S/2017 (113) 1.

[6] One of Jupiter's inner small satellites, unrelated to 113 Amalthea, is also called Amalthea, as is a (apparently fictional) small Arjuna asteroid in Neal Stephenson's 2015 novel Seveneves.