Contacts arising along the Maigue River between Danish Vikings and the Uí Donnabháins provide an insight into the alliance between the two groups in the late 10th century.

[citation needed] John O’Donovan claimed in an appendix to the Annals of the Four Masters[3] that Croom derived its name from Ancrom O'Donovan Crom Ua Donnabáin, who was slain in Innis Beale Antha Dos (now Broadford) in 1254, based on the similarity of Ancrom with Crom.

This event took place only three years after Turlogh O’Brien, King of Munster in 1148, and whom alternatively allied with and opposed Ruaidhrí Ua Conchobhair, defeated the Danes at the nearby fort of Rathmore.

[citation needed] Ultimately, in the early 13th century, the lands surrounding Croom were given to the Fitzgeralds of Kildare.

West of Croom are the ruins of a 15th-century church (National Monument) and a round tower (12th century), the top part of which is missing.

In late 2014, a new Civic Centre was opened which includes a restaurant, library, public computers and function hall.