Can anyone recommend an elegant place to hold a wedding reception?

There is Tappan Hill in Tarrytown which is run by Abigail Kirsch Catering.
If you want something really over the top there is Caramoor In Katonah. Once their International Music Festival is over and the Grand Tent of the Venetian Theater is still up....I helped at a Pre-Season Wedding there. The ceremony was held inside the Rosen House Museum in the Music Room due to the weather and the reception was held in that large tent. They also have the most extensive and proper wash room facilites so you would not have to think about needing "Call A Head"!
My job - to watch the Art Collections!