How can I start searching for family that migrated to US in 1920's?

Question:

How can I start searching for family that migrated to US in 1920's?

Best Answer - Chosen by Asker: Assuming they emigrated from Europe, start with Ellis Island and the Battery Conservancy sites:
http://www.ellisisland.org
http://www.castlegarden.org

At the same time, write to the National Archives Regional Records Center for the state where your family members would have lived and request their immigration and naturalization paperwork. That will give you a wealth of information, particularly the names of their parents and all siblings, where they were born, the name of the ship bringing them over, where it left, where it landed, the date it arrived, any places they lived in the US or abroad after immigration, spouse(s) and children, etc.

Also go through local newspapers for obituaries. Contact the local Clerk of the Court for a death certificate and marriage license(s). Visit the Probate Court to see if a will was filed...it's open to you for viewing and only costs a normal Xeroxing fee to get a copy. You don't give us a lot of info to work with. Where did they migrate from?

Start with yourself and work backward documenting as you go. If we knew where they came from we could help you a little more Go to the earliest census, and type in their last name and their first name, and if you know approximately the date the husband was born it would help. Also the date he died.
This can be great fun. Look in Ancestors.com, you will get three days free to look around.