History
The locality takes its name from its school. A United Methodist Church opened in August 1900. The "neat little building" was and built by Joseph Butters of Toowoomba. Over 300 people attended the opening. Plainby Provisional School opened circa 1889. On 1 January 1909 it became Plainby State School. It closed in 1959. In the , Plainby had a population of 44 people.References
Toowoomba Region Localities in Queensland {{Toowoomba-geo-stub