Ynysddu was founded in the early 19th century by the enlightened local colliery owner John Hodder Moggridge, who lived at nearby Woodfield Park.

Founded as a social experiment 'The Ranks', like similar properties in Blackwood, allowed a few workers to lease a plot of land to build a cottage and garden allotment.

In 1901 Kelly's Directory of Monmouthshire said: "YNYSDDU is a hamlet of this parish, having a station on the Sirhowy section, London and North Western railway, 10¼ miles north-west from Newport.

Pontllanfraith is the nearest money order & Blackwood the nearest telegraph office Board School, erected in 1877, at a cost of £1,500, & erected in 1899, for 167 children; average attendance, 101; Thomas Harries Phillips, master; Miss Susanna Evans, assistant mistress.

Ynysddu is also part of the Celtic Trail cycle route (National Cycle Route 47) which connects West Wales from Fishguard through to Carmarthen, Llanelli, Swansea, Merthyr Tydfil, Newport, and the Severn Bridge in the East.

The club then changed its name to Ynysddu Crusaders AFC in 1915, and existed until the outbreak of WWII in 1939, when it disbanded.

They play their home games at the Nine Mile Point Miners' Welfare Ground at Graig View, which they share with Ynysddu RFC.