When a landscape’s historic context has not been previously established, an adequate level of research must be undertaken to develop the appropriate context for the evaluation of the resource. A research plan should be constructed for the work needed, but it should not exceed that which is necessary to understand the context within which the landscape is to be evaluated. This historic context will place the property’s theme within a time period and geographic area and provide the perspective from which to evaluate the property’s significance. Because a landscape may reflect multiple land uses and physical evolution over many years, it may relate to more than one historic theme or period.

A knowledge of historic contexts provides direction and focus for a survey. It helps surveyors recognize landscape characteristics as integral parts of economic or social systems rather than as isolated features. For example, a drainage ditch may be part of an extensive reclamation system that allowed thousands of acres of valley land to be farmed and settled. A written statement of historic context developed at the beginning of the study can help focus research efforts, and it can be rewritten if necessary as work proceeds. The statement should describe the landscape characteristics that a property must possess to be eligible, such as features reflecting the spatial patterns, land use activities, and water conveyance systems of a historic reclamation district.