Rulemaking is the process used by an administrative agency to formulate, amend, or repeal a rule or regulation. Rulemaking is to be distinguished from legislation, which is the process Congress engages in to enact laws. In the environmental law context, Congress typically establishes a broad legal framework in the various environmental statutes, and administrative agencies, such as EPA, develop implementing regulations that speak with much greater specificity.

In administrative law, rulemaking refers to the process that executive agencies use to create, or promulgate, regulations. In general, legislatures first set broad policy mandates by passing laws, then agencies create more detailed regulations through rulemaking. By bringing detailed scientific expertise to bear on policy, the rulemaking process has powered the success of some of the most notable government achievements of the 20th century.

an open process that evaluates the advantages and disadvantages of a range of alternatives and that invites public input on the alternatives early on and throughout the process