Analysis of information sources in references of the Wikipedia article "Pelion (Illyria)" in English language version.
Escaping one trap, Alexander came to find himself temporarily in difficulty when he moved against Pelium (located somewhere to the west of the Pindus crest which separated Macedonian from Illyrian lands)
An Illyrian chieftain named Cleitus had seized the Macedonian frontier fortress town of Pelium, in the pass between Illyria and Macedonia on the upper Apsos (Devol)
As the fighting among Illyrians was at or near Pelium, we have to put Pelium in Illyria both on the references cited above and also on later statements that it was in Illyria (St. Byz. using Asinius Quadratus), in Dassaretis (Livy 31.40.4).