The Texas Constitution vests broad judicial and administrative powers in the position of County Judge, who presides over a five-member Commissioner's Court. Four Commissioners, each elected to a commissioners precinct representing approximately a quarter of the county's population, serve with the Presiding County Judge on the Commissioners Court.
Members of the Collin County Commissioner's Court also serve as Trustees of the Collin County Health Care Foundation, Collin County Housing Finance Corporation, and the Collin County Substance Abuse Foundation.
In addition to assuring that county roads are maintained, commissioners vote with the county judge to set the budget for all county departments and adopt a tax rate. The County Commissioners Court also:
- Sets the yearly property tax rate and approves the budget and employment level for the county;
- Sets commissioners and justice of the peace precinct boundaries;
- Calls, conducts and certifies elections, including bond elections;
- Sets employment and benefit policy;
- Establishes long-range thoroughfare, open space, land use, financial and law enforcement/jail needs plans;
- Acquires property for rights-of-way or other uses determined to be in the public's best interest;
- Reviews and approve subdivision platting and wastewater treatment for rural areas;
- Provides rural ambulance services and subsidizes rural fire protection;
- Oversees the construction, maintenance and improvement of county roads and bridges;
- Appoints non-elected department heads and standing committees;
- Supervises and controls the county courthouse, county buildings and facilities;
- Adopts a county budget;
- Determines county tax rates;
- Fills vacancies in elective and appointive positions; and
- Has exclusive authority to authorize contracts in the name of the county.