The U.S. Supreme Court recently ruled in Carpenter v. United States that the government must have a warrant to access an individual’s cell phone location history from wireless carriers. The Court held, in a 5–4 opinion issued by Chief Justice Roberts and joined by Justices Ginsburg, Breyer, Sotomayor and Kagan, that individuals have a reasonable expectation of privacy in their cell phone location history, even if shared with third parties. Therefore, the Court held, law enforcement access to a cell phone location history requires a warrant. This ruling is narrow and largely confined to the facts of this case. The Court did not find that location information – in and of itself – is protected by the Fourth Amendment, holding instead that location information sufficient to track an individual’s every movement for four months is protected and would require a warrant. In recognizing that such business records are sometimes entitled to Fourth Amendment protection, the Court also rejected the previous doctrine that disclosure to a third-party categorically waives protection under the Fourth Amendment. The case is expected to have lasting ramifications for privacy concerns in an evolving digital age where third parties often have access to and process private information from individuals in large quantities over protracted periods of time.