Santiago is situated in the province of Isabela some 79 kilometers south of Ilagan (provincial capital town) and about 326 kilometers North from Metro Manila. The city sits on a vast area of predominantly flat and fertile land in the Cagayan Valley, which is surrounded by mountain ranges that include the Caraballo Mountains in the south, the Great Sierra Madre in the east and the Cordillera Mountain Range in the west. In Terms of absolute geographic location, the city lies between 16º35’00” to 16º47’30” north latitude and 121º25’00” to 121º37’00” east longitude.

Although Santiago is located in the southern periphery of Isabela, its economic importance is very much linked to its geographic centrality in the context of the regional space economy. In other words, the growth potential of the city is tremendous given the role that it presently performs in the surrounding area as a bridge in Region 2’s provincial network.

he municipality of Cordon is at the southwestern part of the province of Isabela.  It bounded on the north by the Municipality of Ramon; East by the city of Santiago; South by the Province of Quirino and West by the Province of Nueva Vizcaya.  It lies on Meridians of 121o27’E Longitude and16o40’N Latitude

Cordon has an area of 22,891 hectares unevenly distributed among 26 barangay.  This represents 2.14 percent of the total provincial land area.

Dinapigue is located in the southeastern-most part of the province, near the provincial boundaries of Quirino and Aurora.  It is bounded in the north by Palanan, in the west by Echague, San Guillermo and San Mariano, and in the south by Aurora Province.  It is virtually land locked by Sierra Madre Mountain range on the west and Pacific Ocean in the east.

The municipality is centered approximately in the intersection of geographical coordinates 122 15’40” north latitude and 16 31’45” east longitude.  It is one (1) of the five (5) coastal towns of Isabel with its poblacion situated about 78 kilometers aerial distance from Ilagan, the provincial center of Isabela.

The municipality of Jones is situated in Southern Isabela region.  It is bounded on the east and north by Echague, south by San Agustin and partly by Quirino Province and west also by the Province of Qurino.  It roughly lies between 12’35’ to 122 degrees east longitude, 16’37 north latitude.  It is accessible from the north latitude.  It is accessible from the north via Echague little less than 353 linear kilometers from Manila. 

San Agustin is situated at the southernmost part of Isabela containing an area of 27,840 hectares, with 17,230 hectares of Alienable and Disposable Lands and 10.610 hectares of forestlands.  The municipality of Jones bound it on the west, south and southeast by Quirino Province and on the north to the northeast by the Municipality of Jones, Isabela.

It is composed of 23 barangays.  East of the Cagayan River that bisects the municipality are 14 barangays and on the western side are 9 barangays that include Masaya Centro, the seat of the Municipal Government.