The Affordable Care Act (ACA) is a comprehensive health care reform law enacted in 2010 in the United States. The goal of the ACA is to increase access to affordable health insurance coverage, improve the quality of care, and reduce health care costs. Some key provisions of the ACA include the expansion of Medicaid, the establishment of health insurance marketplaces where individuals can compare and purchase health insurance plans, and the elimination of pre-existing condition exclusions. The ACA also includes provisions for preventive care, mental health services, and prescription drug coverage.