The Collin County Commissioners Court holds authority over the county's administrative services, which include a number of departments such as public works, health care services, facilities, budget, public information, information technology and human resources.

Public Works maintains and builds county roads, as well as oversees trash management for the unincorporated areas of the county. They are about halfway through a program to asphalt all county roads, and stay constantly busy ensuring that county roads remain open and safe regardless of sometimes harsh weather conditions.

In county government, Health Care Services provides indigent health care for qualifying recipients, vaccination programs, the Woman, Infant and Children (WIC) program and epidemiological services. During the past year, the health department, located in McKinney, provided more than 16,000 vaccinations to children and adults, including and more than 2,000 flu immunizations. People seeking additional information regarding health care services can visit the Health Care Services website or call the department directly at (972) 548-5532.

The Animal Services Department was created in 2006. Their facility, located within the Sheriff's Department complex, performs all animal control duties as well as sheltering all lost/stray pets from all unincorporated areas of Collin County, and the cities of Celina, Prosper, Princeton, Fairview, New Hope, Melissa, Nevada, Lavon, and Blue Ridge. McKinney, Frisco, Anna and Farmersville all provide their own animal control services. In FY2013, more than 5,300 dogs and cats came through our shelter.

With three offices across the county, the Tax Assessor and Collector oversees property tax statements and payments. The office also handles all motor vehicle fees on behalf of the state -- such as registration, renewals stickers and license plates.

Residents can access forms and information online, such as regarding the Homestead Exemption, and get answers to property tax-related issues from the Tax Assessor and Collector's pages on the county website.

The County Clerk records the proceedings for the county courts through the County Court at Law Clerks branch office. The County Clerk also maintains a wide variety of legal and vital records that include: Marriage licenses, birth and death certificates, land records, power of attorney filings, bonds, plats, marks and cattle brands, assumed names and beer and wine sales permit applications.

The main function of the District Clerk office is to keep and protect judicial records of the eight District Courts in Collin County. The District Clerk also oversees the accounting and disbursement of all child support payments ordered by the district courts and manages Jury Information Services.

The District Attorney represents the citizens of Collin County in prosecuting misdemeanor and felony crimes, and acts as legal counsel for county government. With more than 50 attorneys, two dozen investigators and about 40 support staff, the office works in cooperation with more than 30 law enforcement agencies in keeping the peace throughout the county by maintaining justice.

The D.A.'s office also runs a pre-indictment plea program and a drug-testing lab program. D.A. investigators, as part of a special unit addressing white-collar crime, oversee a hot-check division and fight mortgage fraud, among other things, and have established an impressive track record in helping local law enforcement close unsolved crimes that have lain dormant for years due to lack of evidence.

Collin County currently has 14​ state District Courts, seven of which oversee general jurisdictional matters: criminal, civil and family law matters. The eighth court focuses solely on juvenile civil and criminal issues. All of these courts reside in the Bloomdale Road courthouse.

Eight County Courts at Law watch over misdemeanor criminal cases and some civil cases, appeals of Class-C misdemeanor convictions, and mental health cases. A separate court exclusively handles probate issues. These courts moved to the main courthouse on Bloomdale Road in 2012.

Another five Justices of the Peace, spread out in sub-courthouses across the county, hold court on issues such as hot checks, truancy, peace bonds, and some traffic violations. They also conduct various magistrate functions including search and arrest warrants, arraignments and examining trials to decide if a criminal suspect should be held on bond until a grand jury votes on a criminal indictment.

The Sheriff is the chief law enforcement officer for the county and is responsible for running the jail, patrolling unincorporated areas and investigating crimes committed in those areas. The county jail is arguably the best in Texas, given that it has passed the stringent state jail inspection for a record 23 years in a row. The Sheriff also keeps a tactical team trained and ready for high-risk situations, narcotics raids and hostage situations, and provides bailiffs for the district and county courts at law.

Four elected Constables and their staffs serve as the chief process servers and bailiffs for the Justices of the Peace courts. Constables execute and return to the courts all warrants, capias warrants, citations, subpoenas, evictions, and writs.

The County Auditor,​ an independent office, ensures the safeguarding, proper handling and appropriate accounting for receipts, disbursements and management of county assets through continuous auditing of transactions. The staff functions as a resource to all officials, departments and other users in the processing, compilation and comprehension of accurate, timely financial information and statistics. The office also monitors allocation of all resources and expenditures while maintaining compliance with all statutes and Commissioners Court policies and mandates.

The Collin County Purchasing Department, another independent office, provides a unified purchasing system that ensures integrity and fairness, with centralized responsibility for oversight of solicitation, vendor selection, negotiation, award, contract management, reporting, and disposal of surplus property for the benefit of Collin County agencies.

The Medical Examiner's Office investigates more than 1,600 deaths and performs more than 200 autopsies a year to determine the cause and manner of death in certain cases, such as suicides and suspected homicides. The office frequently collects evidence in its investigations that are used later in criminal prosecutions, but is also called in when someone dies alone or for unknown reasons. Commissioners court approved the addition of a second pathologist for the office for Fiscal Year 2017.

Emergency Management is responsible for directing and coordinating responses to disasters and emergencies, and to help coordinate different volunteer groups, such as the Medical Reserve Corps, as well as educate the public about disaster awareness issues at home and at work.

The Fire Marshal serves as an advisor, inspector and educator on preventing fires in homes and businesses within the county's boundaries. In addition to fire prevention duties, the office investigates illegal dump sites and addresses nuisance abatement issues.

The Elections Administrator oversees voter registration and manages election tallies at county precincts.

The GIS/Rural Addressing department develops and modifies a geographic database that produces maps, assigns rural emergency 911 street addresses, and performs spatial analyses for the county, which is one of the state's fastest growing counties.