National Alliance to End Homelessness
This is a great resource! From their website, their Mission Statement includes:
The National Alliance to End Homelessness is a nonpartisan, nonprofit organization whose sole purpose is to end homelessness in the United States. We use research and data to find solutions to homelessness; we work with federal and local partners to create a solid base of policy and resources that support those solutions; and then we help communities implement them.
Visit the website here.