Fort Pinell is a location in Fire Emblem: Path of Radiance, and is one of two strongholds that defend the areas due east of Melior, Crimea's capital. The other is Nados Castle, which lies sorth of Fort PInell. The fort is also west of the Marhaut Mountain Range.
In Fire Emblem: Path of Radiance, Fort Pinell is occupied by Daein solders. This is because Ashnard, the king of Daein, had previously invaded Crimea and had taken up residence at in Melior after fleeing Daein. By the time Ike and company return to Crimea, they have already defeated the resistance in Daein, leaving only Ashnard to defeat.
Fort Pinell is the battlefield in Chapter 26 of Path of Radiance. The fort is guarded by General Bertram, one of the Four Riders of Daein. When Soren states that the fort has more soldiers, Ike decides to lead the main army to reclaim Fort Pinell while Tibarn leads another group to attack Nados Castle.