Circular A–16 Supplemental Guidance provides the foundation for a portfolio management approach to nationally significant geospatial data themes and associated datasets under the auspices of Office of Management and Budget (OMB) Circular A–16. It sets the framework for a lifecycle-based portfolio management and reporting process intended to increase the transparency of the development and maintenance of nationally significant datasets. It provides a standard lexicon for use in this process. It offers a decision process for adding, modifying, or deleting specific themes or datasets from Appendix E of OMB Circular A–16 based on alignment with long-term national strategies or goals, specific business requirements, benefits, and costs. We thank the Lifecycle Working Group for this achievement. The product has been transmitted to OMB for final review.