San Mariano is one of the 37 municipalities of Isabela Province. Total population in 2000 was just over 41,000 people, in 36 barangays. San Mariano boomed during the 1960s and 70s when commercial logging companies started to deforest the foothills and slopes of the Sierra Madre Mountains. After logging was banned in the area in the early 1990s, most immigrants that were employed by the logging firms stayed and switched to slash and burn farming. Small scale commercial logging, albeit now illegal, also continued.

In 1997, the Northern Sierra Madre Natural Park was officially declared. San Mariano is one of nine municipalities that have part of their area inside the natural park. The municipality is a hotspot of illegal activities inside the park, mainly logging. The municipal government is trying to make a transition towards more sustainable use of natural resources and is, as mentioned earlier, an active participant in Philippine crocodile conservation.

San Mariano is situated on sloping land, with irrigated rice fields and corn in floodplains, banana plantations on steeper slopes and uninhabited forest on the steep slopes of the Sierra Madre Mountain Range. Four large rivers transport water runoff from the mountains towards Cagayan River. Numerous smaller creeks feed these four rivers. A number of small natural lakes and newly created water impoundments complement the variety in wetlands in the area. It is in these rivers, creeks and lakes that the last surviving wild population of Philippine crocodiles can be found. Intensive agriculture is mainly practiced along rivers. Most settlements are situated along rivers and creeks.

All farmers depend on the availability of water during drier periods and the water holding capacities of forested watersheds during times of superfluous precipitation, such as during typhoons. Nine barangays have been selected as target groups. Selection was based on proximity to crocodile localities. The barangays are: Disulap (1,811 people), Dibuluan (1,158), San Jose (1,551), Dicamay (1,097), Tappa (705), Cadsalan (1,000), Buyasan (568), Macayucayu (520) and Ibuhan (527).

In addition, the project will work with the Municipal Council of San Mariano, which is based in San Mariano Town. The major rivers, clockwise starting at the top end of map 2 are: Catalangan River, Disulap River, Disabungan River and Pinacanauan de Ilagan River. All rivers have their headwaters in the Sierra Madre Mountains, which are situated along a NE – SW direction. In all four rivers Philippine crocodiles have been observed but only Disulap River and a tributary of Pinacanauan de Ilagan River have confirmed breeding areas of C. mindorensis.