The village is located on the banks of the river Clodagh approximately 8 km from Tullamore.

[6] Rahan also has a long association with the Jesuit community who founded a seminary there in the early 19th century (1818) and with the Presentation Sisters who founded a convent and school in the early 19th century (1818 also), both Convent and School have survived to this day.

[7] The monastic site in Rahan contains the remains of church buildings dating from the 11th and 12th centuries and both Protestant and Catholic cemeteries.

The parish of Rahan comprises 44 townlands: Agall, Aghadonagh, Aghalusky, Backsteel, Ballina, Ballincloghan, Ballincur, Ballindrinan, Ballybruncullin, Ballykeenaghan, Blackwood, Bohernagrisna, Brackagh, Cappaloughan, Castletown, Church Hill, Clonshanny, Corcush, Cornalaur, Currygurry, Deerpark, Derries, Derrinvullig, Derrooly, Derrycooly, Derryesker, Derrynanagh, Glasshouse, Goldsmiths Lot, Kilgortin, Killaranny, Killina, Kilpatrick, Loughroe, Mountarmstrong, Murragh, Newtown, Oldtown, Rabbitburrow, Rahan Demense, Roscore Demense, Tullybeg and Tullymorerahan.

[15] The most famous[citation needed] sporting person to come from the parish is Father Nicholas Clavin, All-Ireland winner and All-star Gaelic footballer.

[citation needed] Rahan man Garreth O'Brien captained Offaly to the 1988 All-Ireland under 21 championship.

[citation needed] Rahan native Nigel Dunne is one of Offaly's inter-county players.