The Astor Cup was used in 1915 and 1916 to recognize the winner of the Astor Cup Race which was held at Sheepshead Bay in NY. Vincent Astor, a rich socialite from NYC, donated the winner's trophy, and whose name and connections ensured the attendance of members of New York City's fashionable and wealthy elite.

The Astor Cup Race was a 350-mile race on a 2-mile board track in Sheepshead Bay, N.Y.

That inaugural race was held in October 1915 with a purse of $50,000, a figure matching the Indianapolis 500 purse of that year. Gil Anderson and the Stutz team outlasted a field of 20 to win in 3 hours, 24 minutes, 42 seconds.

Most recently it's given to the winner of the Indycup Championship

http://indymotorspeedway.com/astor_cup.html