 Two years later, US 78/SR 10 were paved from the Gwinnett–Cobb county line to about Snellville.By the end of 1938, US 78N was redesignated as part of the mainline US 78.Also, US 78/SR 10 were paved from about Snellville to Loganville, and from Monroe to the Walton–Oconee county line.