Federal regulation makes a distinction between undertakings that adversely affect historic properties and those that do not (i.e., no-effect and no-adverse-effect findings). The basis for this distinction is whether a federal action will alter or diminish those properties that make a property eligible for listing in the National Register of Historic Places. In other words, not every alteration or change constitutes an adverse effect from a Section 106 perspective. Making that argument, however, requires both a detailed understanding of regulatory definitions and skill in arguing the case. This research would identify and document examples of “making the case” for no-effect and especially no-adverse effect determinations, both of which are the most favorable Section 106 findings for DOTs with direct positive applications in both NEPA and 4(f) analyses.