| Castlelost | |
| Settlement Type: | Civil parish |
| Pushpin Map: | Ireland |
| Pushpin Map Caption: | Location of Castlelost within County Westmeath in the Republic of Ireland |
| Coordinates: | 53.4136°N -7.2942°W |
| Subdivision Type: | Country |
| Subdivision Name: | Ireland |
| Subdivision Type1: | Province |
| Subdivision Name1: | Leinster |
| Subdivision Type2: | County |
| Subdivision Name2: | County Westmeath |
| Blank Name: | Irish grid reference |
| Blank Info: | N469405 |
Castlelost [1] is a civil parish in County Westmeath, Ireland. It is located about 12.81km (07.96miles) south of Mullingar.
Castlelost is one of 10 civil parishes in the barony of Fartullagh in the Province of Leinster. The civil parish covers 9444.4acres.
Castlelost civil parish comprises the village of Rochfortbridge and 16 townlands: Castlelost, Castlelost West, Clontytallon, Derry, Farthingstown, Gallstown, Garrane, Gneevebane, Gortumly, Kilbrennan, Kiltotan and Collinstown, Oldtown, Piercetown, and Rahanine.
The neighbouring civil parishes are: Carrick, Kilbride and Pass of Kilbride to the north, Castlejordan (County Meath) to the east, Castlejordan (County Offaly), Croghan (County Offaly) and Newtown to the south and Clonfad to the West.[2] [3]