List of National parks

1. Mammoth Cave
2. Great Basin
3. Biscayne
4. Everglades
5. Smokey Mountains
6. Arches
7. Acadia
8. American Samoa
9. Badlands
10. Big Bend
11. Black Canyon of the Gunnison
12. Bryce canyon
13. Canyonlands
14. Capitol Reef
15. Channel Islands
16. Congaree
17. Crater lake
18. Cuyahoga valley
19. Death Valley
20. Denali
21. Carlsbad Caverns
22. Dry Tortugas
23. Gates of the Arctic
24. Glacier
25. Glacier Bay
26. Grand Canyon
27. Grand teton
28. Great Sand Dunes
29. Great Smokey Mountains
30. Guadulupe Mountains
31. Haleakala
32. Hawaii Volcanoes 
33. Hot Springs
34. Isle Royale
35. Joshua Tree
36. Katmai
37. Kenai Fjords
38. Kings Canyon
39. Kobuk Valley 
40. Lake Clark
41. Lassen Volcanic
42. Mesa Verde
43. Mount Rainier
44. Sequoia
45. Rocky Mountain
46. Red Wood
47. Olympic
48. Theodere Roosevelt

http://en.wikipedia.org/wiki/List_of_national_parks_of_the_United_States