Founding and Early Days: Thornhill was founded in 1891 by Thomas Thornton, a visionary industrialist inspired by the potential of the region's natural resources and strategic location along the railway branch line. The town was initially established to support the mining operations of the Thornhill Coal Mine, which extracted high-quality coal from deep underground.

Coal Mining Era: The late 19th and early 20th centuries marked Thornhill's coal mining boom. The Thornhill Coal Mine became a major employer in the region, attracting a diverse workforce seeking opportunities underground. Coal mining families settled in the town, contributing to its cultural diversity.

Post-World War II Changes: After World War II, Thornhill experienced significant changes. The coal mine, which had fueled the town's economy for decades, eventually ceased operations due to declining demand for coal and economic factors. This shift brought challenges, including job losses and economic uncertainty.

Industrial Renaissance: In the 1960s, Thornhill underwent an industrial renaissance. A modern chemical plant was established in 1965, bringing new job opportunities and diversifying the local economy. The plant produced a range of chemicals used in various industries, including agriculture and manufacturing.

Manufacturing Growth: During the same period, a manufacturing plant specializing in heavy equipment production was established in Thornhill. This facility produced robust machinery used in construction, mining, and agriculture, contributing to the town's economic resurgence.

Cultural Adaptation: As Thornhill transformed from a coal mining town to an industrial center, the community adapted to these changes. The town's cultural landscape evolved, with new traditions and a focus on education and technological innovation.

1990s Rail Revival: The rail line connecting Thornhill to the Scajaquada Valley Northern Railway was revived in the mid-1990s, marking a return to rail operations in the town. This revitalized transportation link played a key role in supporting Thornhill's growing industries and enhancing its connectivity to regional markets.

Town Name Inspiration: The town was named "Thornhill" in honor of its founder, Thomas Thornton. His vision and leadership in establishing the coal mine and supporting the early development of the town made him a respected figure in the community. The name also reflects the idea of Thornville as a place of resilience, symbolizing the town's ability to adapt and thrive despite the challenges it faced, particularly during the transition from coal mining to modern industrialization.

Today, Thornville is a dynamic and diverse community known for its modern industrial sectors, technological innovation, and a commitment to preserving its cultural heritage. The town continues to evolve while honoring its past and the contributions of its founder, Thomas Thornton.