Personal jurisdiction is the authority a court has to make legally enforceable orders related to a person or entity and the property of the person or entity, and usually arises when a person has been sued in a lawsuit. For a court to have personal jurisdiction, the person or entity generally (1) must be a resident of the state in which the court is located; (2) as a nonresident, must have initiated sufficient minimum contacts with the state in which the lawsuit is filed; or (3) must have agreed to be governed by the laws of the state (in a contract or website terms) in which the lawsuit is filed.

In New Hampshire, personal jurisdiction refers to the power of a New Hampshire court to bring a person or entity into its court process and to make decisions that are legally binding upon them. The state follows the general principles of personal jurisdiction found throughout the United States. Firstly, if a person or entity is a resident of New Hampshire, the state courts typically have jurisdiction. Secondly, for nonresidents, New Hampshire courts can claim personal jurisdiction if the nonresident has established 'minimum contacts' with the state. This concept, stemming from the U.S. Supreme Court case International Shoe Co. v. Washington, requires that the nonresident's contacts with the state be such that the maintenance of the lawsuit does not offend 'traditional notions of fair play and substantial justice.' Activities that might create minimum contacts include conducting business in the state, owning property, or committing a tort within the state. Lastly, a person or entity can consent to the jurisdiction of New Hampshire courts by agreeing to it in a contract, such as including a forum selection clause in terms of service or other agreements. New Hampshire courts will also consider the due process clause of the Fourteenth Amendment to ensure that exercising jurisdiction is fair and just.