Risca (Welsh: Rhisga) is a town in the Caerphilly County Borough and within the historic boundaries of Monmouthshire in south-east Wales. It has a population of 11,228.

The town lies at the south-eastern edge of the South Wales Coalfield and has been shaped by mining, together with other heavy industries, for many centuries.

Risca is home to Ty-Sign, a large housing estate built in the early 1960s as a satellite village for the then new Llanwern steelworks.

Risca has a rural aspect and is surrounded to the east and west by several extensively wooded hills, including Mynydd Machen (1,188 ft; 362 m) and Twmbarlwm (1,375 ft; 419 m), which attract tourists for the hillwalking and mountain bikers to Cwmcarn Forest Drive.

Risca has a railway station on the Ebbw Valley Railway, reopened in February 2008.

There is evidence of human habitation in the Risca area going back thousands of years, such as the Silures hillfort on nearby Twmbarlwm; however, the area was rural and sparsely populated until the nineteenth century. As local industries expanded and transport links improved with the building of the canal and railways, the population rapidly increased.

Several arguments have been put forward for the derivation of the name Risca/Rhisga including that it comes from the Welsh yr is cae, meaning "the lower field", or yr hesg cae, meaning "field or rushes", or rhisgl, meaning oak bark.

The earliest known official use of the name Risca for the place was in 1476 when two men from Risca were charged at the Newport Assizes, although there are also ecclesiastical documents going as far back as 1146 which include mentions of a man called Kadmore de Risca.