It covers 110.04 square kilometres (42.49 sq mi) and had a population of 941 as of the 2021 Canadian census.
Sainte-Germaine-Boulé was first settled in 1922 when the family of Noël Boucher and Marie Couillard moved in.
One year later a visit of Mgr Rhéaume was organized to fix the location of a future church.
The sector continued to develop at a steady pace until 1954 when it officially became its own separate municipality from Palmarolle, as well as by gaining territory from the nearby Poularies.
The original name of the new municipality was Sainte-Germaine-de-Palmarolle but it was changed to Sainte-Germaine-Boulé five months later.