Although the fee for not having health insurance was reduced to $0 on a federal level starting 2019, some states still have an individual mandate for 2019 forward. Here is a list of states where you have to buy health insurance.
States that have their own mandate include: the District of Columbia, Massachusetts, New Jersey, and Vermont (starting 2020).
States considering a mandate for the future: California, Connecticut, Hawaii, Maryland, Minnesota Rhode Island, and Washington.
NOTE: State mandates are subject to change, please make sure you understand your responsibilities as a taxpayer before choosing to enroll or not.