This study uses a behavioral approach to measure the impact of a partial eminent domain land taking (which affects easement rights and causes proximity damage) on residential property values. Existing appraisal methods are not suited to handle this type of unique valuation impact determination, yet diminution must be determined by the courts to establish proper “just compensation”. To accomplish the quantification of damages, an experimental design is implemented that allows the market to voice its opinion of valuation impact through a mechanism other than direct comparable sales. Moreover, this behavioral methodology can and should be used in a number of additional real estate valuation applications.