Skysports.com understands United are tracking the highly-rated Black Cats starlet.
A number of clubs are thought to be chasing the 20-year-old following a number of impressive performances for club and country over the last 12 months.
Chelsea and Manchester City are believed to be keeping tabs on Henderson, but United are hoping to steal a march on their rivals for the young Wearsider.
United boss Sir Alex Ferguson and his assistant Mike Phelan were interested observers at Sunderland's Premier League clash at Blackburn on Monday night and Henderson was thought to be the reason for their attendance at Ewood Park.
Ferguson is understood to be keen to reshape his midfield options and he sees Henderson as a player with a bright future ahead of him
Sunderland are desperate to keep hold of Henderson, but they could face it difficult to turn down a sizeable offer from any of the midfielder's suitors.