Llanishen grew from a small village into a substantial conurbation after the arrival of the railway in the mid 19th century, enabling commuting to Cardiff. By 1922, after continued expansion, Llanishen became a suburb of Cardiff. In 1939 the government established a large Royal Ordnance Factory at Llanishen and after the war, a large area around the factory became the site for large housing developments, industrial units and government offices.

RCAHMW, 2013.

References:
Ordnance Survey historic mapping
Llanishen Local History Society website