The Madison Road. Depending on where you count it from, since the 1820s, there has been a road connecting Indianapolis, Franklin, Columbus, Vernon and Madison. Just like the railroad of the same name.
SR 7 was the number given to the road from Columbus to Madison. Most of this route still exists with very little modification. The route had been truncated at the Columbus end, making SR 46 the Columbus entry from the south and east.
Indiana Transportation History 