Mercer County has a County Executive form of government, in which the County Executive performs executive functions and a Board of Chosen Freeholders acts in a legislative capacity.  Members of the seven-person Board of Chosen Freeholders are elected at-large to serve three-year staggered terms. The Board is led by a Freeholder Chair and Vice-Chair, selected on an annual basis from among its members.

The Freeholder Board 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. After receiving the proposed county budget from the County Executive in January of each year, it is the duty of the Freeholder Board to thoroughly review, make appropriate changes, and then vote on the budget.