The 94.1 kilometres (58.5 mi) Tambellup to Ongerup branch line from the Great Southern Railway main line between Perth and Albany was opened to Gnowangerup on 1 July 1912, and finally through to Ongerup on 6 January 1913. The line was developed to provide direct access for the expanding wheat production area to the port at Albany. The line was authorised for construction under the Tambellup-Ongerup Railway Act 1911.
A timetable from 1937 shows two trains per week leaving Ongerup on Tuesdays at 06:55 and Fridays at 04:00. Lengthy connections of around 12 hours were available at Katanning for Perth, arriving approximately 30 hours after leaving Ongerup.
The line went via Tambellup, Dartnall, Toolbrunup, Pallinup, Gnowangerup, Formby, Kebaringup, Borden, Laurier, Toompup and Ongerup. Water supply for the trains was provided at Formby.
In 1918 a barracks was constructed on Eldridge Street for railway workers based in Ongerup. The building survived the closure of the railway and now houses the Ongerup and Needilup District Museum, opened in 1978.
In 1986 the Gnowangerup Railway Station building was closed as a working station and remained unused until 2000, when it was dismantled and moved to the Lily Vineyard, near Borden, where it was rebuilt in 2003 as a restaurant.
The section of line from Gnowangerup to Ongerup was closed on 13 October 1957. The Tambellup to Gnowangerup section was closed in July 2007.