For more information on policing in Massachusetts, see entry on Boston Police.
- Partnership/Ownership/Membership – Anti-Defamation League (ADL)
In 2017, the Sheriff from the Plymouth County Sheriff's Department participated in a "counterterrorism seminar" in Israel, as part of an all-expenses-paid delegation of US law enforcement to Israel sponsored by the New England chapter of the Anti-Defamation League (ADL). The New England Chapter of the Anti-Defamation League (ADL) sponsors annual all-expenses-paid delegations to Israel for high-ranking New England police, ICE, FBI, and other security officials, where these officials meet with Israeli military, police, and intelligence agencies, with whom they train and exchange tactics including surveillance, racial profiling, crowd control, and the containment of protests.
- Partnership/Ownership/Membership – Greater Boston Police Council
The Plymouth County Sheriff's Department is listed as a full member of the Greater Boston Police Council, a "law enforcement council" (LEC) set up in the 1970s to link regional police forces and share resources for policing anti-war protests. LECs in Massachusetts have played a central role in militarizing police by organizing SWAT teams and purchasing military equipment such as Lenco Bearcats and other armored vehicles.
- Partnership/Ownership/Membership – Southeast Regional Homeland Security Advisory Council (SRHSAC)
Major Daniel Callahan and Sheriff Joseph McDonald Jr. from the the Plymouth County Sheriff's Office are both members of the Southeast Regional Homeland Security Advisory Council.
- Partnership/Ownership/Membership – Metropolitan Law Enforcement Council (Metro LEC)
The Plymouth County Sheriff's Department is a member agency of the Metropolitan Law Enforcement Council (Metro LEC). Like other Law Enforcement Councils (LECs) in Massachusetts, Metro LEC functions to increase regional collaboration between police and sheriff's departments, while organizing SWAT teams and obtaining military equipment for use by its member agencies and operating largely out of public view as a semi-private organization.