Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), a United States federal law designed to clean up sites contaminated with hazardous substances. Superfund created the Agency for Toxic Substances and Disease Registry (ATSDR), and it provides broad federal authority to clean up releases or threatened releases of hazardous substances that may endanger public health or the environment. The law authorized the Environmental Protection Agency (EPA) to identify parties responsible for contamination of sites and compel the parties to clean up the sites. Where responsible parties cannot be found, the Agency is authorized to clean up sites itself, using a special trust fund.

CERCLA was enacted by Congress in 1980 in response to the threat of hazardous waste sites, typified by the Love Canal disaster in New York, and the Valley of the Drums in Kentucky.

The EPA published the first Hazard Ranking System (HRS) in 1981, and the first National Priorities List (NPL) in 1982. The implementation during early years has been criticized as being ineffective due to the Reagan administration's laissez-faire policies. During his two terms, 16 of the 799 Superfund sites were cleaned up, and $40 million of $700 million in recoverable funds from responsible parties were collected.