Moyashel and Magheradernon (Irish: Maigh Asail agus Machaire Ó dTiarnáin)[1] is a barony in the centre of County Westmeath, in Ireland, formed by 1672.

[2] It is bordered by eight other baronies: Corkaree and Fore (to the north), Delvin and Farbill (to the east), Fartullagh and Moycashel (to the south) and Rathconrath and Moygoish (to the west).

[2] The barony contains parts of two large lakes; Lough Ennell, shared with the barony of Fartullagh, and Lough Owel, an internationally recognised Ramsar waterfowl habitat.

The N4, a national primary road passes through the barony to the north of Mullingar, connecting Dublin with the northwest of Ireland and the coastal town of Sligo.

Railway lines carrying the national rail company Iarnród Éireann's Dublin to Longford commuter service and Dublin to Sligo intercity service[4] stop in the barony at Mullingar railway station.