Documentation should be as detailed and thorough as needed to provide adequate information and justification to obtain concurrence in the study’s conclusions. Comprehensive studies are not needed if ineligibility is easily determined or when a small landscape is evaluated within a established historic context. However, a study of a large, complex landscape which appears to be eligible could require in-depth historical documentation, multiple inventory forms, and a substantial number of maps and photographs. Where eligibility status is unclear, or where there are multiple resources or periods of significance, a substantial amount of work is often required. (See Section VI, below, for approaches to documenting large landscapes.) Before beginning a major effort, consult project managers to consider possible avoidance alternatives.

With certain publicly owned properties, it can be useful to develop documentation to the full level specified in National Register bulletins. These bulletins typically focus on documenting, recording, and listing eligible properties, providing a level of information that is particularly beneficial for long-term management of publicly owned eligible resources. For other project studies conducted in compliance with federal and state laws, the level of documentation should be that which is needed to demonstrate eligibility status and gain SHPO concurrence. It must be appropriate for the resource, adequate to convey necessary information and justify findings, but not excessive. On the other hand, skimping on documentation to rush completion is counter-productive when lack of critical information creates delays in the review process. It is especially important to develop a clear argument for eligibility or ineligibility and to determine boundaries and identify contributors and noncontributors for eligible historic landscapes. On large or difficult projects, or when unusual circumstances apply, early consultation with the SHPO is recommended.

In addition to preparing standard documentation, it may be appropriate to consider large-format maps with overlays, aerial photographs, scale models, or videotapes. Computers also offer ever-greater opportunities for conveying information, and multimedia presentations can be invaluable to understanding a large or complex historic landscape. Before committing substantial amounts of time or resources to such efforts, it would be well to consult review agencies and ensure that reviewers will be able to take advantage of the results. For example, first check to see if the review agency has the equipment to view videotapes, compatible computer capabilities for electronic submittals, or the space for large graphics or scale models. Sophisticated documentation is useful only if it will be available and convenient for reviewers. Meanwhile, the standard written report, complete in itself with maps and photographs, remains the basic documentation; it should not be dependent on other media that may not always be available.