Find used electronic computer equipment wholesaler in the US?

Hi

can anyone tell me where can we find the companies they are wholesaler of used computer and electronic and Cisco equipment?

while i was searching i understood in Sharjah, UAE, there are lots of wholesaler of these equipment, i found them in google map, but i love to know where and which place into the US we can find much more of these companies, i am sure there is an area which we can find much of these products, but i dont know how can i find them.