NCSS is the umbrella professional organization for social studies teachers, including all the academic disciplines associated with history and social science. The site has been re-designed to include grant opportunities and conferences and courseware. Resources are listed with connections to the NCSS themes–handy for alignment of content and standards.
National Council for the Social Studies
Resource Link: https://www.socialstudies.org/
( Link may be down. We are checking into it. )