Units on regional and national maps are usually associations of great groups or suborders. Accompanying descriptive material is usually brief, as in the National Atlas of the United States of America .
Some regional maps have accompanying booklets.
General soil maps at the small scales of regional and national soil maps are used for studying very broadly defined capabilities and limitations that affect regional and national issues. They are useful in relating areas of similar soils for transferring technology and exchanging research results. Interpretations for broad land uses and estimates of limitations and suitabilities can be made to the degree permitted by the scale of the map and the heterogeneity of the map units. The map is organized at two levels of generalizationsoil orders and associations of great groups. The text discusses each soil order of the region, including its geography, landscape, relief, vegetation, land-use considerations, and soil mineralogy, as well as the distinguishing features of the major soils in the order.