A significant Roman Catholic Church and a road connecting Camarag to other places like Santiago and Nueva Vizcaya were constructed, and the ruins of these landmarks still exist today.

Seventeen years later, in 1856, it became a town of Isabela, along with others such as Cabagan, Tumauini, Ilagan, Gamu, Angadanan, Carig (present-day Santiago), Palanan, Alamo, Gaddang, Mayoyao, Brengiones, and Catalaganes.

Additionally, Katuray was surrounded by barangays producing high-quality tobacco and had fertile soil ideal for agriculture.

[6] The opening of the San Jose-Santa Fee road in the 1920s facilitated the movement of people from Ilocos and Central Luzon to the Cagayan Valley, with many settling in Camarag.

Leaders among these new settlers included Benito Tumamao, Vicente Ramos, Ramon Felipe, Tomas Galapia, and Alejandro Viloria.

[6] On June 17, 1967, Republic Act 5139, authored by Representative Melanio T. Singson, became law, creating the municipality of San Isidro.

[6] Today, while the Ilokanos remain the dominant group in San Isidro, the municipality is home to a diverse population.

Tagalogs, Pangasinense, Ibanags, Gaddangs, and others have made San Isidro their place of residence and commerce.

Poverty incidence of San Isidro Source: Philippine Statistics Authority[13][14][15][16][17][18][19][20] As a municipality in the Province of Isabela, government officials in the provincial level are voted by the electorates of the town.

San Isidro, belonging to the sixth legislative district of the province of Isabela, currently represented by Hon.