McIlroy got off to a good start in his quest for his first PGA Tour win since the 2012 PGA Championship.
Henley carded a 6-under 64 at PGA National Resort & Spa.
Tommy Gainey, Brice Garnett, Matt Every, Brandon de Jonge and Derek Ernst were tied for sixth with rounds of 4-under 66.
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Teacher apologizes for showing sexual image of herself in class