OpenCelliD
OpenCelliD is a collaborative community project that collects GPS positions of cell towers and their corresponding location area identity.
More than 49,000 contributors are registered with OpenCelliD, contributing more than 1 million new measurements every day on average to the OpenCelliD database. As of August 21, 2017 the database contained 35.5 million unique cells and 2.1 billion unique measurements.
OpenCelliD publishes an aggregate data set of cell locations licensed under a Creative Commons Attribution-ShareAlike 4.0 International License with the intention of promoting free use and redistribution of the data.