https://qz.com/1312339/this-supreme-court-ruling-means-cellphone-location-data-is-now-the-last-vestige-of-your-privacy/

If you’re in the US and concerned about data privacy, you can breathe a little easier today (June 22). The nation’s highest court just ruled that cellphone location data is protected by the Fourth Amendment of the US Constitution.

The ruling in Carpenter v. US (pdf) protects not only digital privacy, but freedom of movement. A divided Supreme Court, split 5-4 with a plethora of dissenting opinions issued, held that “an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through” cell signal location information (CSLI). That means police need a warrant based on probable cause in order to obtain your records from cellphone companies.