The below states operate their own health insurance marketplace instead of using the federal marketplace. These states are:
| State | Open Enrollment Period |
| Arkansas | Nov 1 - Jan 15 |
| California | Nov 1 - Jan 31 |
| Colorado | Nov 1 - Jan 15 |
| Connecticut | Nov 1 - Jan 15 |
| Idaho | Oct 15 - Dec 15 |
| Kentucky | Nov 1 - Jan 15 |
| Maine | Nov 1 - Jan 15 |
| Maryland | Nov 1 - Jan 15 |
| Massachusetts | Nov 1 - Jan 23 |
| Minnesota | Nov 1 - Jan 15 |
| Nevada | Nov 1 - Jan 15 |
| New Jersey | Nov 1 - Jan 31 |
| New Mexico | Nov 1 - Jan 15 |
| New York | Nov 1 - Jan 31 |
| Pennsylvania | Nov 1 - Jan 15 |
| Rhode Island | Nov 1 - Jan 31 |
| Vermont | Nov 1 - Jan 15 |
| Virginia | Nov 1 - Jan 15 |
| Washington | Nov 1 - Jan 15 |
| Washington, D.C. | Nov 1 - Jan 31 |
In these states, individuals can shop for and purchase health insurance plans that meet the requirements of the Affordable Care Act (ACA) through their state marketplace instead of using the federal marketplace at healthcare.gov. These state-based marketplaces may have different rules and options than the federal marketplace, but they still offer the same essential health benefits and protections required by the ACA.