It is a mountain near the Jordan River.
After entering Canaan, God divided the tribes of Israel into two, placing one group on Mount Ebal and the other on Mount Gerizim, making them swear to revere God for generations.
For more details, refer to Ebal (place name).
Additionally, when there was a dispute between Gideon's son Abimelech and Jotham, Jotham expressed his grievances and anger on Mount Gerizim.
Judges 9:7When they told Jotham, he went and stood on top of Mount Gerizim and shouted to them, “Listen to me, citizens of Shechem, so that God may listen to you.