Brunswick County provides complete local government services. The county is divided into five magisterial districts, each of which is represented by one supervisor elected to serve four years.

These officials form the Board of Supervisors, the legislative body of the county. The Board of Supervisors elects a chairman from its membership for a one-year term. The Board of Supervisors holds regular monthly meetings, and may schedule additional meetings if necessary. The Board appoints a county administrator, who serves as the county's chief administrative officer under the board's direction.

The Board of Supervisors is responsible for establishing local public policy, raising local resources for the support of public programs, and overseeing the conduct of the county's affairs through its appointed administrative officials. County government, as a political subdivision of the state, also assists in the local implementation of state laws and programs.

The Code of Virginia states that the County Board of Supervisors shall have the power to:

• Prepare and approve the county budget
• Levy taxes and appropriate funds
• Audit claims against the county
• Issue warrants in settlement of all claims and accounts
• Construct and maintain county buildings
• Approve and enforce the county's comprehensive plan and land use control ordinances
• Make and enforce ordinances for police, sanitation, health, and environmental government as authorized by law
• Provide for the care and treatment of indigent and physically handicapped county citizens