The cost per square foot in South of Market — also known as SoMa — is $5,415. Just over 120 miles away is Northwest Auburn, California, the second-highest priced U.S. neighborhood at $4,416 per square foot. The Old Town neighborhood of the beachside California town of Carpinteria comes in third in the rankings, with a cost per square foot of $4,129. In contrast, the Homewood North neighborhood in Pittsburgh ranks last amongst the 20,000 neighborhoods examined for the study, with homes costing $29 per square foot. The rankings are based on average price per square foot data for U.S. homes using Homes.com listing data.