Where did Jehoshaphat's people assemble to bless the LORD after their enemies were destroyed?

Answer: The Valley of Beracah

After three days gathering plunder, on the fourth day they blessed the LORD in a valley still called the Valley of Beracah.

“On the fourth day they assembled in the Valley of Beracah, where they blessed the LORD. Therefore that place is called the Valley of Beracah to this day.”— 2 Chronicles 20:26 (BSB)