Hell's Kitchen Flea Market is located on 39th Street, between 9th and 10th Avenues. While in the past the area might have been considered on the "outskirts" of Manhattan, it is now crowded with high rise buildings, and, subsequently, more human traffic. It is also close to Port Authority Bus Terminal and Times Square.
This outdoor market is open on Saturday and Sunday from 9am-5pm all year long. You can find great antiques, art deco home decor, vintage clothing, jewelry and more. With the upcoming plans for expanding the High Line in Manhattan, this market is going to be even more accessible to tourists.