The Board of County Commissioners acts as a formulator of policy and provides a check on the powers of the County Executive. The Board also approves all county contracts and gives advice and consent to the County Executive’s appointments of department heads, and appointments to boards and commissions. It is the duty of the Commissioners to thoroughly review, make appropriate changes, and then vote on the budget.

The County Commissioners' powers include:

• adopting the County's Administrative Code
• passing ordinances and resolutions
• reviewing, modifying, and adopting all operating and capital budgets
• evaluating and studying the County's Annual Budget before final approval
• making contracts with municipalities in the county

The County Commissioners oversee the provision of funds for all county departments to include:

• Mercer County Community College
• Vocational-Technical School
• Mercer County Board of Social Services
• Mercer County's correctional facilities, County Sheriff and the County Court House
• Mercer County Improvement Authority
• Mercer County Park Commission
• Mercer County Library Systems