There are many national organizations you can partner with to help with your STEM programming.  Universities and colleges, science centers and museums, federal science agencies, science and engineering professional societies, and of course other youth development groups all make strong partners.  A few partners with existing STEM education initiatives you can reach out to include:

• Association of Science and Technology Centers (ASTC): Science Centers and museums have great hands-on activities and exhibits for field trips, they offer professional development opportunities, and will sometimes even come out to your program site to run the program with you. Contact your local science center and see what they have to offer you!
   
• Center for Advancement of Informal Science Education (CAISE):  Supported by the National Science Foundation, CAISE works to strengthen and connect the informal science education community.  
   
• Coalition for Science Afterschool: Dedicated to promote STEM learning in afterschool.  Check out their myriad resources, including research on STEM in afterschool in their Publications section.

•  Connect a Million Minds: An initiative from Time Warner Cable to connect children and youth with afterschool STEM programs in their local area.  Search the "Connectory" for activities and resources in your community. 

•  Great Science for Girls: A national initiative, funded by NSF, to provide inquiry-based, informal science programs that enhance girls' curiosity, interest and persistence in STEM, and counteract the effects of bias. Working with intermediary organizations and afterschool programs, GSG delivers curricula, research, and professional development that support and promote the concept that science is, indeed, a girl thing.

• National Girls Collaborative Project: An extraordinary resource for girl-serving organizations to talk to each other about their efforts to bring more girls and young women into the STEM pipeline.  Check out their mini-grants to get a little pot of money to support collaborative work.
   
• National Lab Network: Formerly called National Lab Day, this is a nationwide initiative to build support locally within communities by partnering educators with volunteers, content experts, and resources in your area.  You can enter a project description, location information, and ask for volunteers or scientists and engineers in your neck-of-the-woods to work with you. You can even ask for funding resources. Register on the site to learn more.
   
• Last but not least, professional research scientists funded by the National Science Foundation and NASA are required to engage in education and public outreach efforts.  They can make great partners in K-12 STEM education with their deep content understanding, experience with teaching, and most importantly - desire to engage in meaningful education/outreach efforts.  Don’t hesitate to contact science and engineering departments at your local college or university to ask if you can come in and have a conversation about your STEM programming needs.