In the United States, a district attorney (DA), county attorney, county prosecutor, state's attorney, prosecuting attorney, commonwealth's attorney, state attorney or solicitor is the chief prosecutor or chief law enforcement officer representing a U.S. state in a local government area, typically a county or a group of counties. The exact scope of the office varies by state. Generally, the prosecutor represents the people of the jurisdiction. With the exception of three states, district attorneys are elected, unlike similar roles in other common law jurisdictions.

A prosecutor is a legal representative of the prosecution in states with either the adversarial system, which is adopted in common law, or inquisitorial system, which is adopted in civil law. The prosecution is the legal party responsible for presenting the case in a criminal trial against the defendant, an individual accused of breaking the law. Typically, the prosecutor represents the state or the government in the case brought against the accused person.