“Alava” was formerly a vast eastern part of the municipality of San Fabian, which became an independent municipality from 1867-1918. The name “Alava” was given by a high Spanish military official in memory of his home province named Alava on the northern part of Spain, which coincidentally, is also in the northern part of Pangasinan. The Alava town was formerly composed of the barrios of Cabuanan, Camanggaan, Bolaoen, Binmeckeg, Cabaritan, Cauringan, Amagbagan and Asan and several sitios as Overbiong, Pugo, Batakil, Paldit, Macoco and Reriet.
During the tribal years, several “ranchereas”were organized on the north and east portions of the town of Alava by migrating people seeking rich soil for subsistence. There were the defunct “ranchereas of Colisao (now part of San Fabian), Pinmilapil, Esperanza, Dungon, Agat, Sagunto and Bila. These ranchereas were grouped into one to form the township of Esperanza and made Esperanza the site of its government office under the Special or Insular Government from 1900 to 1907.
On the other hand, there were also ranchereas on the east of the Aloragat River, namely: Inmalog, Labayug, Calunetan, Alibeng, Bacayao, Casilagan and San Andres. These ranchereas were grouped into one township. Labayug was the center of Special or Insular Government from 1900 to 1907.
From 1907 to 1918, Labayug and Esperanza were fused together and formed a big township. It was named after Provincial Governor Artacho who initiated the fusion.
After some years, the Municipality of Alava planned to widen its territories to be able to add revenue collections and maintain its government. On the other hand, the municipality of Artacho, also on the move to become a regular municipality, offered Alava to fuse with her. Alava had no alternative and agreed to fuse with the town of Artacho in order to become a big regular municipality with sufficient revenue to maintain its government.
On May 11, 1918, a bill sponsored by then Senator Pedro Maria Sison was approved in Congress effecting the fusion of the township of Artacho and Alava as decreed by then Governor General Leonard Wood. The town was named SISON in honor of its sponsor - Senator Pedro Ma. Sison.
From then on, the municipality of Sison became an independent town.
MEANING OF MUNICIPAL SEAL
Shield - Derived from the provincial seal of Pangasinan where the town is located
Mallet and Chisel - Signify woodcarving as one of the sources of income of Townspeople
Plow - Symbolizes agriculture, the principal means of livelihood of the people.
Factory - Stands for the Northern Cement Corporation representing the cement industry of the town
Twenty Eight (28) Palay Grains - Depict the twenty eight (28) barangays comprising the Municipality