This research analyzes spatial and temporal variation in the effects of lot size and proximity to open space on residential home values in a single Tennessee county. The findings show that the value of proximity to greenways, parks, and water bodies increased over time, while the value of lot size and proximity to golf courses fell. Proximity to open space is found to be a substitute for lot size, although the degree of substitutability has weakened over time. Geographic variation in the marginal effects of lot size and proximity to open space is analyzed using locally weighted regression analysis. (JEL C31, Q51)