Morphology: croes+maen
Phonetic: groys-vine
An area near Deri in the Darran Valley, it is also the name of a farm between this village and nearby Aberbargoed and was also the name of a colliery. Groesfaen Colliery was the deepest in the Darran valley (2160 feet) and was in full operation from around 1908 for sixty years and employed about 730 men. The colliery closed in 1968. The word "croes" means cross and "maen" means stone, but rather than literally meaning "stone cross", here it means "a stone crossing", referring to a stone bridge over the river dating back to the 17th century.