Medicare is a government-funded healthcare program in the United States that provides medical coverage primarily for individuals aged 65 and older, as well as for certain younger individuals with disabilities. It was established in 1965 as part of the Social Security Act and is administered by the Centers for Medicare & Medicaid Services (CMS).

Medicare provides health insurance coverage for a wide range of services, including hospital care (Medicare Part A), medical insurance for doctor visits, outpatient care, and medical supplies (Medicare Part B), Medicare Advantage plans (Medicare Part C), and prescription drug coverage (Medicare Part D).

Medicare Part A helps cover inpatient care in hospitals, skilled nursing facilities, hospice care, and some home healthcare services. Part B covers medically necessary services such as doctor visits, preventive care, outpatient care, and durable medical equipment.

Part C allows beneficiaries to receive their Medicare benefits through private health insurance plans, often including additional benefits beyond what Original Medicare offers. Part D provides prescription drug coverage, which can be added to Original Medicare or included in a Medicare Advantage plan.

While Medicare covers a significant portion of healthcare costs, it does not cover all expenses. Beneficiaries are responsible for paying certain deductibles, copayments, and coinsurance amounts.

To be eligible for Medicare, individuals generally need to be U.S. citizens or permanent residents who have worked and paid Medicare taxes for a specified period. Some individuals may also qualify for Medicare based on specific disabilities or certain medical conditions.

It's important to note that Medicare is separate from Medicaid, which is a healthcare program primarily intended for low-income individuals and families.