Where can I find detailed lists of housing companies/contacts by state?

n the United States, housing co-ops are usually catagorized as corporations or LLC's and are found in abundance in the Greater New York metropolitan area, and more precisely within New York City itself, Westchester County, New York (which borders the city to the north) and towns in New Jersey that are immediately across the Hudson River from Manhattan, such as Fort Lee, Edgewater, or Weehawken. Unlike in other parts of the world, most of these housing co-ops did not develop as a result of social engineering. Apartment buildings and multiple-family housing simply make up a more significant share of the housing stock in the New York City area than in most other US cities, and the cooperative form of ownership has dominated over the condominium form.

Best site for it is

http://www.lcsys.net/wib/Companies/sic_test.asp