Receiving Gift of $100,000

Hi all,

 

My wife receive a cash gift (cash transferred into her account) from her sister in the amount of $100,000. I understand her sister would need to file Form 709 as the giver, and my wife as a receiver doesn't have to do anything. But, wouldn't IRS like to know how a $100,000 pops up on her account? My wife and I file a join-return, should we not say anything about it on our tax forms? Would VA state tax us on the money?

 

Thank you for any input you could provide.