American Viticultural Areas (AVAs) are descriptors of where wine grapes are grown that are designed to capture qualities unique to the wine and to influence its price. Sub-AVAs are sub- divisions of well-known AVAs designed to have the same effect. In this paper, I study the impact of the Napa Valley Sub-AVA system on the pricing and rating of Napa Valley wines. The analysis utilizes a primary hedonic pricing model to isolate both the individual Sub-AVA’s price effect and the system’s cumulative price effect. This study uses a unique dataset of 5,017 Napa Valley wines reviewed by the Connoisseurs’ Guide to California Wine over the 10-year period from 2004–2013. Estimated price effects persist even after controlling for rating differences, implying that consumers value the wines of sub-AVA’s independently of critics’ ratings. These results indicate that Sub-AVAs deliver a more substantial price effect than previous literature has suggested.