Possible Clues:

• Red, white and blue land, for short
• 'Merica, with "the"
• The States, colloquially
• ''Good old'' place
• Uncle Sam's land, humorously
• 18-Across' country, informally
• Stars-and-stripes land, for short
• Its b’day is July 4
• 'Red, white and blue' land, for short
• The States, casually