Most Common Gulf in Crossword Puzzles: It's MEXICO (Gulf of Mexico)

The answer is MEXICO (referring to the Gulf of Mexico).

It's a crossword staple because:

• 6 letters – fits many grid slots.
• High vowel/consonant alternation (M-E-X-I-C-O) – crosses well.
• Universally known geography.
• Frequent clue: "Gulf ____" or "____ Gulf."

Other common gulf answers: ADEN (4), OMAN (4, Gulf of Oman), TONKIN (6), CALIFORNIA (10, Gulf of California), PANAMA (6, Gulf of Panama). But MEXICO appears far most often.