"Over the Coquille-Bandon Highway from its junction with the Oregon Coast Highway, US101, at the east city limits of Bandon, easterly to its junction with the Coos Bay-Roseburg Highway, OR42, in Coquille."
~ ODOT, Descriptions of US and Oregon Routes, March 2007
OR-42S has had a relatively short life in Oregon's highway system. It was created out of an older portion of US-101 between Coquille and Bandon in 1961 when a new alignment of US-101 was build between Coos Bay and Bandon. The remaining portion of former US-101 was turned into a western extension of OR-42. There haven't been any changes along the highway since then.