As an agent of the state, the county government serves the entire county in these ways: (1) through elected officials, it administers and enforces state laws, collects taxes, assesses property, records public documents, conducts elections, issues licenses; (2) through appointed boards and officials, it provides parks, libraries, sewers, emergency management, public assistance, and hospitals. As required by state law, the county government also serves unincorporated areas by providing such purely local government facilities and services as highways, police protection, building inspection, planning, and zoning. Elected county officials oversee most of these services. A city or village may contract with the county to receive a service.

Belmont County has no top executive and no single overall governing body. Responsibility for county government is shared by the Ohio General Assembly that has legislative power; the county courts that have judicial powers and a three-person board of county commissioners and eight other county officials who have administrative powers. Also participating in the Belmont County government are a number of semi-independent boards and commissions created by the state, or permitted by state law and created by the authorities specified when the need arises.

The chart below describes how major county functions are divided between the board of county commissioners, other elected officials, and various boards and commissions.