The Municipality of Sison is located in the northeastern portion of Pangasinan lying within the provincial boundaries of La Union and Benguet. Its boundaries are Rosario, La Union on the north, Pozorrubio, Pangasinan on the south, San Manuel and Binalonan, Pangasinan on the southeast, Tuba, Benguet on the northeast and San Fabian, Pangasinan on the west.
Sison is accessible by land transportation through Pozorrubio – Binalonan – Baguio – Manila Road. It is approximately 200 kilometers north of Manila and it takes approximately 4 hours to travel by bus, 50 kilometers south of San Fernando City where the regional offices of the national government agencies in Region 1 are located and it takes approximately 2 hours to travel by bus, 53 kilometers east of Lingayen (via Pozorrubio) and it takes approximately 2 hours to travel by bus, and 43 kilometers south of Baguio City and it takes approximately 2 hours to travel by bus.
The municipality falls under Type I climate which is characterized by two (2) pronounced seasons, the wet and dry. Dry season covers November to April, while wet or rainy season is from May to October. Average annual rainfall is 2,391.70mm or an average monthly rainfall of 199.31mm witrh heavy rainfall occurring during the months of June to September. The driest month is January while the wettest month is August with 3.00mm and 608.60mm rainfall, respectively, from 1971 to 2000. The month of August has the highest number of rainy days with 23 while January and February have only one rainy day. Average monthly temperature is 27.9°C. May is the hottest month with the average temperature of approximately 27.88 degrees centigrade and December and January are the coldest months with approximately 25.4 degrees Celsius. Normally, the month of August registers the highest rainfall and humidity. May is the hottest month with the average temperature of approximately 27.88 degrees centigrade and December and January are the coldest months with approximately 25.40 degrees Celsius.
Sison is composed of twenty eight (28) barangays wherein 5 barangays namely: Poblacion Central, Poblacion Norte, Poblacion Sur, Paldit and Labayug are considered urban barangays and the rest are all rural barangays. It also has 50 sitios mostly located in the mountain barangays of the municipality. The municipality belongs to the 5th Congressional District of Pangasinan. It is governed by the Local Government Code of 1991 and its officials are elected by the people and serve their constituents for a three-year tenure.