This document is a supplement to the Presidents 2021 Budget Request to Congress. It describes research and development coordination activities planned for FY2021 by the Federal agencies participating in the Networking and Information Technology Research and Development (NITRD) Program. It reports actual investments for FY2019, estimated investments for FY2020, and requested funding levels for FY2021 by agency and Program Component Area (PCA). For the FY2021 budget request, this Supplement identifies strategic priorities, key programs, and key coordination activities for each NITRD PCA. An appendix to the Supplement, FY2021 Federal Cybersecurity R&D Strategic Plan Implementation Roadmap, lists existing and proposed Federal R&D projects and programs that address the Nations critical cybersecurity challenges.