Final answer:
The National Center for Health Statistics (NCHS) under the CDC is responsible for maintaining the United States' vital statistics. The United States Census Bureau conducts surveys and census but does not manage vital events records.
Step-by-step explanation:
The federal agency responsible for maintaining official vital statistics in the United States is the National Center for Health Statistics (NCHS), which is a part of the Centers for Disease Control and Prevention (CDC). The United States Census Bureau, another important agency, is known for conducting the decennial census and other surveys, but vital statistics such as marriage, birth, and death certificates are more specifically managed by the NCHS.
The data collected on these vital events is critical for public health and policy planning and is usually coordinated through state and local health departments rather than directly by Washington authorities.