 In 1933 and 1934, the Marion section was extended north to State Route 42.The final piece in Smyth County was added in 1936; the gap in Tazewell County was filled in 1937 and 1938.The whole piece of present SR 16 from State Route 12 (now U.S. Route 58) at Mouth of Wilson southwest to North Carolina Highway 681 (now North Carolina Highway 16) was added in 1931 as State Route 139.