10 CARPENTER v. UNITED STATES Opinion of the Court [bank] employees in the ordinary course of business.” Id., at 442. The Court thus concluded that Miller had “take[n] the risk, in revealing his affairs to another, that the information [would] be conveyed by that person to the Government.” Id., at 443. Three years later, Smith applied the same principles in the context of information conveyed to a telephone company. The Court ruled that the Government’s use of a pen register—a device that recorded the outgoing phone numbers dialed on a landline telephone—was not a search. Noting the pen register’s “limited capabilities,” the Court “doubt[ed] that people in general entertain any actual expectation of privacy in the numbers they dial.” 442 U. S., at 742. Telephone subscribers know, after all, that the numbers are used by the telephone company “for a variety of legitimate business purposes,” including routing calls. Id., at 743. And at any rate, the Court explained, such an expectation “is not one that society is prepared to recognize as reasonable.” Ibid. (internal quotation marks omitted). When Smith placed a call, he “voluntarily conveyed” the dialed numbers to the phone company by “expos[ing] that information to its equipment in the ordinary course of business.” Id., at 744 (internal quotation marks omitted). Once again, we held that the defendant “assumed the risk” that the company’s records “would be divulged to police.” Id., at 745. III The question we confront today is how to apply the Fourth Amendment to a new phenomenon: the ability to chronicle a person’s past movements through the record of his cell phone signals. Such tracking partakes of many of the qualities of the GPS monitoring we considered in Jones. Much like GPS tracking of a vehicle, cell phone location information is detailed, encyclopedic, and effortlessly compiled.