Possible Clues:

• Where the Platte R. flows
• Lincoln’s home: Abbr.
• Bad Lands state: Abbr.
• Okla. rival
• The Missouri R. forms its eastern border
• Homestead Natl. Monument locale
• Buzzard's beak, e.g.
• Part of the La. Purchase
• Henry Fonda's birthplace: Abbr.
• SD's neighbor