The depth at which fence posts should be set depends on various factors such as the height and type of the fence, as well as local soil conditions. As a general rule, it is recommended that at least one-third of the posts length is buried underground. For example, a 6-foot tall post would typically require setting it about 2 feet deep into the ground. However, in areas with loose or sandy soils like some parts found in North Carolina, deeper holes may be necessary for added stability.