OpenCellID is the world's largest collaborative community project that collects GPS positions of cell towers, used free of charge, for a multitude of commercial and private purposes.

More than 49,000 contributors have already registered with OpenCellID, contributing more than 1 million new measurements every day in average to the OpenCellID database. Detailed statistics are available in real time.

The OpenCellID project was primarily created to serve as a data source for GSM localisation. As of Jan, 2015, the database contained almost 7 million unique GSM Cell IDs and 1.2 Billion measurements.