Stress states in the Earth’s crust are of fundamental importance, they determine how rocks deform, how fracture and fold patterns develop and how faults behave. In general, stresses are separated into neo- and paleo-stress, and different methods give mainly reduced stress tensors, focusing on magnitude or direction of stresses or give only mean and differential stress. Neo-stresses can be measured directly in bore-holes, tunnels and mines or calculated using Earthquake data. In order to understand paleo-stress states of the Earth’s crust it is important to find stress gauges that capture the old stress states. In this session we want to discuss different neo- and paleo-stress gauges (borehole-breakout data, fault slip data, calcite twin studies and roughness studies of stylolites) and modeling of stress states. Our main aim is to bring together various research groups that work on these topics. We would like to discuss the different methods and find potential ways to merge or combine them. In addition we welcome contributions that have used methods to study paleo-stress states of different regions in order to discuss stress states of the Earth’s crust in general.