Techniques for pillar location for a mobile device are described, and may be implemented via a mobile device to identify frequently visited locations and to perform different tasks for the mobile device at the frequented locations. Generally, the described techniques enable a mobile device to generate precise representations of frequented locations known as “pillar locations” without relying on conventional location determination techniques. Further, specific actions can be performed when the mobile device is detected at a pillar location, such as automatically unlocking the mobile device from a locked state.