In Middle-earth during the Second and Third Ages, there were several roads of great import to travellers. It is safe to assume that these were the lifelines of trade and communication between kingdoms. They were:

All of this information was taken from J.R.R. Tolkien's Unfinished Tales, specifically page 462 in the index, and the maps at the back of the book. This edition of Unfinished Tales was put out by Unwin Paperbacks in London, England, and published in 1980.