1998 U.S. Open may refer to:

• 1998 U.S. Open (golf), a major golf tournament
• 1998 US Open (tennis), a Grand Slam tennis tournament
• 1998 Lamar Hunt U.S. Open Cup, a soccer tournament for U.S. teams

• St. Helens, Oregon
• St Helens Park, New South Wales
• St Helens R.F.C.
• St. Helen's (skyscraper)
• St Helens South (UK Parliament constituency)
• St Helens, Tasmania
• St Helens Town A.F.C.
• St Helens Town FC
• St Helens & Wigan Junction Railway
• St Helier
• St. Helier
• St Helier, London
• St Helier railway station
• St Heliers Correctional Centre
• Sthene
• Sthenelus
• Sthenno
• Stheno
• Sthenolagnia
• St. Henri
• St. Henri (electoral district)
• St. Henry (electoral district)
• St. Henry, OH
• St. Henry, Ohio
• St. Herman of Alaska