What vehicle can travel the farthest on a gallon of fuel?

The vehicle that can travel the farthest on a gallon of fuel is typically a highly fuel-efficient hybrid or electric vehicle, such as the Toyota Prius, which can achieve impressive miles per gallon (MPG) ratings. However, if considering conventional vehicles, some small, efficient diesel cars or specialized vehicles like the hypermiling setups can exceed standard efficiency metrics. In terms of real-world performance, the exact vehicle may vary depending on driving conditions and techniques used.