Best for 4x4s
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Padre Island National Seashore, Texas

Everything is bigger in Texas, and that goes double for Padre Island. With 90 miles of pristine beachfront, Padre is the planet's longest undeveloped barrier island – beloved by windsurfers and beachcombers alike. Past the cluster of resorts at either end, you'll find a paradise of sandy beaches, wind-carved dunes, and lonely grasslands. The best access requires four-wheel drive; tread carefully in July, when endangered Kemp's ridley sea turtles lay their eggs.