Both players are central defenders and have 242 Premier League appearances between them.
Leeds head coach Uwe Rosler is looking to strengthen his defence and has identified McAuley and Williamson as possible targets alongside Liam Moore from Leicester City.
McAuley, 35, is out of contract at the Baggies this summer and Leeds face competition to sign the Northern Irish international.
A number of Championship and Premier League clubs are thought to be chasing the centre-back and Leeds United are the latest to join that list.
Mike Williamson is set to fall down the pecking order at Newcastle as the Toon look to pull themselves away from another relegation battle next season.
The 31-year-old made 31 appearances in the Premier League this season, scoring on one occasion.
It is set to be a busy summer at Elland Road, with a number of players expected to join the club.
Leeds United players return to pre-season training in 3 weeks time and the club will want to add new faces as soon as possible.