Multiple choice general knowledge The longest highway in the world has a length of about 4000 km about 12000 km about 8000 km about 6464 km Reveal answer Fill a bubble to check yourself C Correct answer Explanation The Trans-Canada Highway spans approximately 7,821 km (about 8,000 km), making it the longest national highway system. This coast-to-coast highway connects Victoria, British Columbia to St. John's, Newfoundland.