The Valley of the End was where they fought during Part I. Naruto claimed Sasuke chose the location because of the connection it shares to both of them from the previous fight, but Sasuke simply claimed he wanted to finish what he started that day, meaning he wanted to kill Naruto this time, rather than spare him like he did in the last fight. Also, the Valley of the End is also where Hashirama and Madara fought, and quite a bit of Naruto and Sasuke's fight battle here, mirrors the battle those two had as well.