Justices of the peace are judges who handle both civil and criminal cases, including small claims court, justice court, and administrative hearings. In practical terms, these are lawsuits over debts, evictions, car accidents, unlawful towing, and property.

Their criminal workload involves disposing of all class C criminal misdemeanor complaints, such as traffic citations, issuance of bad check, and others. These cases involve payment, setting contested cases for trial, and pretrial hearings with the county prosecutor.

Other duties include presiding over peace bond hearings, reviewing applications for mental health or chemically dependent commitments, conducting compulsory school attendance trials, and giving warnings to juveniles required by law. They issue warrants for and conduct hearings concerning seizure and disposition of cruelly treated animals. Most justices of the peace perform marriage ceremonies as well.

In New Mexico, justices of the peace are not a part of the modern judicial system. Instead, New Mexico has a magistrate court system that handles many of the functions traditionally associated with justices of the peace. Magistrate courts in New Mexico have jurisdiction over certain misdemeanor criminal cases, including traffic violations and DWI cases, as well as civil cases involving amounts up to $10,000, such as small claims disputes. They also handle landlord-tenant disputes, including evictions. Magistrate judges can issue arrest and search warrants, and they have the authority to conduct preliminary hearings in criminal cases to determine if there is enough evidence to bind a case over for trial in district court. While magistrate judges in New Mexico may perform marriage ceremonies, they do not typically preside over peace bond hearings, mental health commitments, or compulsory school attendance trials, as these matters are handled by other courts or administrative bodies within the state. It's important to note that the specific duties and jurisdiction of magistrate courts can vary by county, and for certain matters, individuals may need to consult with an attorney for guidance.