Whether this non-Russian region should be the only beneficiary of a “Pious Fund” was the subject of the first case before the Principal Court of Arbitration. This region was divided from its northern neighbor by the Palóu line, putting it under the control of the Dominicans. After trying to invade a region to the east of this region, later Nicaraguan filibusterer (-5[1])William Walker retreated to this region, where the Battle of (*) La Paz took place. Eusebio Kino convinced Europeans (10[1])that this region was a peninsula, (10[1])not an island. (-5[3])Before heading directly north to found new missions, Junípero (10[1])Serra oversaw this region’s missions. For 10 points, name this Mexican region which contains Tijuana and is south of a similarly named American state. ■END■ (10[4])