There were no other persons in the vehicle.
On Sunday evening, a van entered the water at approximately 5.30pm.
The scene is currently preserved, and Gardaí are appealing for witnesses to come forward.
Any road users who may have camera footage (including dash-cam) and were travelling in the area are asked to make this footage available to investigating Gardaí.
Anyone with any information is asked to contact Birr Garda Station on 057 9169 710, the Garda Confidential Line on 1800 666 111, or any Garda Station.