The City of Santiago is a city in the province of Isabela

Isabela province

Isabela is the second largest province of the Philippines next to Palawan. It is located in the Cagayan Valley Region in Luzon. Its capital is Ilagan and borders, clockwise from the south, Aurora, Quirino, Nueva Vizcaya, Ifugao, Mountain Province, Kalinga, and Cagayan...

, Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

. According to the latest census, it has a population of 126,244 people in 22,401 households. Santiago is situated 79 kilometers south of Ilagan, the provincial capital, and about 326 kilometers North of Metro Manila

Metro Manila

Metropolitan Manila , the National Capital Region , or simply Metro Manila, is the metropolitan region encompassing the City of Manila and its surrounding areas in the Philippines...

. The city sits on a vast area of predominantly flat and fertile land in the Cagayan Valley

Cagayan Valley

Cagayan Valley is a region of the Philippines, also designated as Region II or Region 02. It is composed of five provinces, namely: Batanes, Cagayan, Isabela, Nueva Vizcaya, and Quirino...

, surrounded by the Caraballo Mountains

Caraballo Mountains

Caraballo Mountains is a mountain range in the central part of Luzon, Philippines. It is located between Cordillera Central and Sierra Madre mountain ranges, at .This Caraballo Mountains are the location of the headwaters of the Cagayan River....

 to the south, the Great Sierra Madre

Sierra Madre (Philippines)

The Sierra Madre is a mountain range in The Philippines. It is located along the north-eastern coast of Luzon Island, running north/south. Quezon National Forest Park is situated in the range.-Geography:...

 to the east and the Cordillera Mountain Range to the west.

Although Santiago is located at the southern end of Isabela, it is centrally located in the region and therefore plays an important part in the regional economy.
The origin of Santiago City can be drawn from the first native settlement discovered by the early Spanish missionaries at the bank of the old Carig River (now Diadi River) from which its original name, Carig, was derived.