Plas Dinam was designed and built by the renowned London based architect W E Nesfield in 1873-74 for Captain Offley Crewe-Read, deputy lieutenant of the county and JP, and a descendant of the ancient Crewe family of Flintshire and Cheshire. The family did not ever actually live at Plas Dinam, and sold it when they ran into financial difficulty.
In 1884 Plas Dinam was bought by David Davies of Llandinam. Despite having been born into a humble family and starting work as a sawyer, David Davies went on to make a considerable fortune building the new railway line across Wales. He played a major role in the construction of the Newtown to Aberystwyth railway, and then turned his attention to the rapidly expanding coal industry.
Plas Dinam has been a family home since 1883. Plas Dinam was home to Gwendoline and Margaret Davies who collected a significant impressionist collection in the early 1900s. It now belongs to the National Museum of Wales in Cardiff.