The Cultural Resources Historian provides both general historical background studies for transportation project areas, and detailed histories of specific historic archeological sites, architectural resources, and bridges. This information is compiled from sources ranging from primary documents and secondary works to oral interviews. Historical overviews at the county level aid in the interpretation and evaluation of particular historic properties, placing them in a broader context of cultural continuity and change. These regional histories chronicle the past settlement patterns; the development of local communities; economic trends, such as growth and transitions in agriculture, mining, lumbering, and manufacturing; directions in population dynamics; immigration and ethnicity; and major transportation developments such as railroads and highways. More localized histories focus on the project area to provide more detailed information about the particular locale, and the potential significance of identified properties. Detailed histories of the specific archeological sites and architectural resources, placed within their broader contexts, evaluate and document their historical significance through information such as the period of occupation, the associated owners and occupants, and their place in local, state, or national history. The documentation of historic bridges provide details of their engineering, construction histories, information on the contractors involved, and their roles in the larger transportation system.