Sioux City is the county seat of Woodbury County, but a portion of it extends into Plymouth County. Sioux City, with a 2018 estimated population of 82,396, could be home to a number of people suffering from opioid use disorder. The city has a total area of 154.4 km² and it is one of the largest cities in the U.S. state of Iowa. Residents of the city or nearby ones who wish to medically treat opioid addiction may find assistance in any methadone clinic in Sioux City Iowa. Methadone is a long-lasting, effective opioid agonist. It minimizes the psychological and physical effects of opioids in the body. It is so effective that the World Health Organization included it in the list of essential medications. Although it is effective, methadone is regulated to ensure the safety of program enrollees and avoid diversion into the illicit market. Part of the regulation is that the medication-assisted treatment practitioner must have the complete health history of the patient before putting them under methadone maintenance. Also, the patient is to be told every possible side effects and health risks of the program. Only patients who show interest after the information may be treated with methadone. All methadone clinics in Iowa are required to register with the Drug Enforcement Administration.