The objective of this research was to investigate the effect of terroir (geographical location of milk source) on Cheddar cheese flavor. Milk from 5 locations, including single dairy farms and commingled sites, were collected from around the state of Oregon: 3 individual dairy farms from the mid-valley and 2 commingled sites at coastal and high desert plateau. These farms/sites were selected based on their representation of Oregon’s dairy industry as well as similarities in herd and herd management characteristics. Using raw and pasteurized counterparts of the standardized milk, Cheddar cheese was made and aged. At 5 and 9 mo into aging, Cheddar cheese consumers were asked to sort the samples based on perceived similarity/dissimilarity of cheese flavor and also to describe the characteristics of each cheese groups. Grouping data were subjected to multidimensional scaling and subsequent cluster analysis. Correspondence analysis was also performed on consumer descriptions as a simplified exploratory approach to discover underlying characteristics. Results at 5 mo into aging revealed that consumers could differentiate cheese samples based on dairy farm origin, while cheeses produced from commingled milk samples were perceived to be similar. At 9 mo into aging, consumers differentiated the cheeses based on heat treatment; that is, raw vs. pasteurized milk cheeses. These data suggest that for younger cheeses, the geographical location of the milk source has a significant effect on the flavor of Cheddar cheese but that the practice of milk commingling may overcome the effects of geographical location. Thus we can source cheese flavor to individual farms and thereby demonstrate the existence of terroir. In contrast, the older cheeses are primarily characterized by their history of heat treatment.