Springfield police arrested 44 people after a multi-week investigation in the areas of Union, School, High and Temple streets.
Authorities said they also seized 14 illegal firearms and more than 1,000 grams of fentanyl.
“Between the fentanyl seized and the weapons recovered, there is no question that our officers saved several lives during this operation,” Springfield Police Superintendent Cheryl C. Clapprood said.
Clapprood added that its firearms investigation unit has seized more than 350 illegal firearms.
“I am extremely proud of the work our SPD does every day under the leadership of Superintendent Clapprood,” added Springfield Mayor Domenic Sarno.