I Cavalry Corps had a detached division that fought at the battle in which present-day country?
I Cavalry Corps (Grande Armée):  The army included a I Cavalry Corps led by Pierre Claude Pajol which fought at Ligny and Wavre, while one detached division fought at Waterloo. Battle of Waterloo: The Battle of Waterloo was fought on Sunday, 18 June 1815, near Waterloo in present-day Belgium, then part of the United Kingdom of the Netherlands.
Belgium