A trench is a linear excavation in the ground, often with the extra earth sandbagged and piled in front and back of the trench. Like foxholes, trenches offer infantry good cover against fire of most kinds; however they can hold more men and also allow covered movement.
In CMx2, trenches are automatically linked with trenches in adjacent squares during setup. Trenches placed by themselves may not point themselves as you would like. Unfortunately, Face is not implemented for trenches. To orient trenches you must take a second trench and place it next to the one you are trying to orient. The first will then reorient automatically to attach to the second. Once it is oriented correctly, then you can put the second trench back where it was.