Gelligaer lies 6 miles north west of Caerphilly in Caerphilly County, South Wales. It is bordered to the north by Penpedairheol, to the south by Ystrad Mynach, Fleur de Lis to the east and Trelewis to the west, with surrounding towns and villages including Bargoed, Blackwood, Abercynon, Nelson, Tredegar and Oakdale.

There are many walks criss-crossing the hills and valleys and the Rhymny Valley Ridgeway Walk cuts through Gelligaer as it weaves its way across the undulating hills of the South Wales Valleys.

The village church is dedicated to St Catwg and dates back to medieval times. In the late 15th century Jasper Tudor, uncle of Henry VII, gave the church the gift of bells and an organ, as a thank you to the Lord of Glamorgan for his support to the Tudor family. The bells remained until 1650. The church was later restored in 1866, when work was done on the collapsed roof and on the nave. In the 20th century larger windows were added to the south side of the church.

Parc Penallta Country Park lies just 1 mile south of Gelligaer and includes beautiful woodland and parklands. Sultan the pit pony, known as Britain's largest figurative earth sculpture, can be found here, and many trails lead you to exciting parts of the park, where Lapwings and Skylarks can be seen in their natural habitat.