It is the largest province in the island of Luzon and the second largest province in the Philippines by land area .
Isabela comprises an aggregate land area of 12,414.93 square kilometres ( 4,793.43 sq mi ) , representing almost 40 percent of the regional territory .
Isabela is the largest province in the island of Luzon and the second largest province in the Philippines by land area .
Isabela comprises an aggregate land area of 12,414.93 square kilometres ( 4,793.43 sq mi ) , representing almost 40 percent of the regional territory .