How Are Grand Juries Chosen?

Jury Box I
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According to, a grand jury is "a jury, at common law, of 12 to 23 persons, designated to inquire into alleged violations of the law in order to ascertain whether the evidence is sufficient to warrant trial." Grand juries act as the first step in the process of evaluating evidence and deciding whether there should be a criminal charge brought against a defendant. Given their important role in our justice system, grand jury members represent a cross-section of the community.

The Grand Jury Pool

The pool of potential grand jurors includes all persons living in the community under the court's jurisdiction. The court randomly chooses grand juror candidates from among this pool. The clerk of courts identifies candidates from public records such as registered voters and licensed drivers.

Read More: How to Defer Jury Duty


U.S. law requires that everyone selected for federal grand jury duty be U.S. citizens over the age of 18, and having lived within the court's judicial district for at least one year. Jurors must be sufficiently fluent in the English language to complete the court's selection questionnaire and have no pending felony charges or felony convictions on their records. They also must have no physical or mental disabilities making them unable to serve.


To determine the eligibility of prospective jurors, the clerk of the court sends each a mandatory questionnaire to complete and return. The court then randomly selects grand jurors from among the candidates eligible to serve according to their questionnaire answers. Each selected juror receives a summons to appear for jury duty at the courthouse on the scheduled date and time.


Selected jurors may request an exemption from serving on the grand jury under certain conditions. Courts generally excuse jurors in public safely professions (such as police or nurses), and those over a certain age if they request it. Additionally, courts may excuse others from duty if their service would create an "undue hardship or extreme inconvenience." This includes someone who is the sole caregiver for a disabled family member, someone without the means to reach the courthouse, or someone scheduled for surgery in the immediate future.

Terms of Service

Grand jurors generally must serve one or two days each week for anywhere from 12 to 24 months, depending on the type of grand jury--county, state or federal. Fortunately for those chosen, citizens need not serve on more than one grand jury, or serve as both a grand and petit juror, within any two-year period.

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