Route 66 (Chicago to Santa Monica)

Running 2,448 miles from Chicago Loop to Santa Monica Pier, Route 66 is the original American road trip, crossing eight states and fifty years of roadside culture. Decommissioned in 1985, surviving sections preserve neon signs and diners where a patty melt costs under $10. The Painted Desert spans 93,500 acres of technicolor badlands, while Cadillac Ranch in Amarillo features ten Cadillacs buried nose-first at a 33-degree angle. This route sees 85% of its traffic between May and September, making shoulder seasons a quieter upgrade. Denser with nostalgia than #2? No, but it offers three times the vintage motel options per mile of any other on this list.