OCTOBER TERM, 2017 (Slip Opinion) 1 Syllabus NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337. SUPREME COURT OF THE UNITED STATES Syllabus CARPENTER v. UNITED STATES CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT No. 16–402. Argued November 29, 2017—Decided June 22, 2018 Cell phones perform their wide and growing variety of functions by continuously connecting to a set of radio antennas called “cell sites.” Each time a phone connects to a cell site, it generates a time-stamped record known as cell-site location information (CSLI). Wireless carriers collect and store this information for their own business purposes. Here, after the FBI identified the cell phone numbers of several robbery suspects, prosecutors were granted court orders to obtain the suspects’ cell phone records under the Stored Communications Act. Wireless carriers produced CSLI for petitioner Timothy Carpenter’s phone, and the Government was able to obtain 12,898 location points cataloging Carpenter’s movements over 127 days—an average of 101 data points per day. Carpenter moved to suppress the data, arguing that the Government’s seizure of the records without obtaining a warrant supported by probable cause violated the Fourth Amendment. The District Court denied the motion, and prosecutors used the records at trial to show that Carpenter’s phone was near four of the robbery locations at the time those robberies occurred. Carpenter was convicted. The Sixth Circuit affirmed, holding that Carpenter lacked a reasonable expectation of privacy in the location information collected by the FBI because he had shared that information with his wireless carriers. Held: 1. The Government’s acquisition of Carpenter’s cell-site records was a Fourth Amendment search. Pp. 4–18. (a) The Fourth Amendment protects not only property interests but certain expectations of privacy as well. Katz v. United States, 389 U. S. 347, 351. Thus, when an individual “seeks to preserve something as private,” and his expectation of privacy is “one that society is