Deri is situated in the heart of Caerphilly County, South Wales. It is bordered to the south by Bargoed, to the north by Pentwyn, to the west by Bedlinog and to the east by Brithdir, with nearby towns and villages including Tredegar, Rhymney, Ebbw Vale, Blackwood and Merthyr Tydfil.
North of Deri is Parc Cwm Darran country park, which consists of beautiful woodland, parkland, meadows and a lake. Scenic routes lead you through the landscapes of the Rhymney Valley, whilst more active visitors can take one of the cycle trails. A coffee shop can also be found here, offering both hot and cold drinks and snacks.
There are many walks criss-crossing the hills and valleys and the Rhymney Valley Ridgeway Walk passes close to the village.