Let’s go back in time. About 30 seconds ago (before you read the N340 title of this post). Back then, if I had asked you what the longest major road in Spain is, what would you have said? You might have thought about the big autovias (freeways) in Spain like the A-7. After all, it starts close to the border with France and ends near Algeciras. let’s go back to the future. Now that we’re back where we started, you know that the N-340 is the Longest road in Spain.