Yornup's name is of Noongar origin. It was primarily a milling settlement, and Greenacres Mill continues to this day. A timber company, Lewis and Reid, built a mill in town that was sold in 1923 to Bunning Brothers who upgraded the mill in 1935 and continued to operate until 1951 when the Donnelly River mill commenced operations.
A railway line between the Donnelly Mill and Yornup was built in 1948 and remained in use until the last steam train was retired in 1970.
At one point, Yornup had a school, post office, hall and stores; only the hall remains today, used for community dances. The school was relocated to the rear of 144 Hampton Street, Bridgetown, in March 1996 in anticipation of the construction of a heritage precinct which never eventuated. A large Western Power substation is located in the town, and an industrial estate is proposed for the area.
- "Register of Heritage Places - Assessment Documentation" (PDF). 1991. Retrieved 7 November 2010.
- "Morowa Historical Society - Ghosttowns of Western Australia" (PDF). 2000. Retrieved 7 November 2010.