Where did Jesus pray the high priestly prayer?

The prayer commonly referred to as "the high priestly prayer" (John 17) was prayed after the Lord Jesus had left the upper room with his eleven disciples (John 13:41) and before He crossed over the ravine of the Kidron on His way to the Garden of Gethsemene (John 18:1). In fact, the intercession of the Great High Priest is continuing even now in heaven itself in the presence of God the Father (Romans 8:34; Hebrews 9:24).