The seven-time Tour de France winner ran the marathon in November for the first time and finished 856th, barely beating his goal finishing in less than three hours.
After finishing the 42.2-kilometer (26.2-mile) race in November, Armstrong called it "without a doubt the hardest physical thing I have ever done."
"Hawaii would be too hot. I couldn't run a marathon there," he said, adding that the scope of the New York race will help fundraising possibilities for his charity, The Lance Armstrong Foundation.
Armstrong joined members of the panel on Monday in Jackson to discuss research and public policy about tobacco.
"Smoking is something that is clearly deadly, not just for the people that choose to do it but for the people around them as well," Armstrong said.