The ACLU has a great website that describes your rights in a large number of situations.  This link is to the entry point  where you can select the area of concern.

All people in the United States, regardless of immigration status, have certain rights and protections under the U.S. Constitution. The ILRC's red cards give examples of how people can exercise these rights. However, they do not provide individualized legal advice. Community members are encouraged to check in with a trusted legal service provider for questions about their situation.