What are some specific addresses where homeless people congregate in
the cities below?

I am talking about specific addresses, like "1600 North Spring Street,
San Jose, CA" or "Shelby Street, 1300-1400, Dallas, TX".   I'm trying
to pin the locations on a Google map so I need specifics.   The more
the better.

Here are the cities I need:

New York, NY
Los Angeles, CA
Dallas, TX
San Francisco, CA
San Jose, CA
Boston, MA
Seattle, WA
Portland, OR
Denver, CO
Atlanta, GA
Chicago, IL
Washington, DC
Phoenix, AZ
Houston, TX
Miami, FL
Fargo, ND
Austin, TX
Philadelphia, PA
San Diego, CA
Detroit, MI
Salt Lake City, UT
Sacramento, CA
Long Beach, CA
Reno, NV

Hello  hatihati-ga,

It sounds like you want the researcher to research multiple general
locations in 24 cities and then do the research to get the exact
street adress for each of them. This would be a $5 question if someone
had already collected this information and you just had to find the
link. Unfortunately, this is not the case and this question will
require hours of research. Since you're a fairly new user of Google
Answers, I recommend that you review these links so that you can
maximize your experience with this service.

http://answers.google.com/answers/faq.html
http://answers.google.com/answers/pricing.html

All the best.

~ czh ~

Homeless people would probably be found at:
Homeless shelters (if they exist in the U.S.A).
Places where food is distributed free to homeless people (soup kitchens).
Public Parks

As for specific addresses, try Welfare Department/Community
Welfare/Community Services or what ever organisation tries to help
homeless people.