Borough Park: D-SNPs, IB-Dual, and the “default enrollment” letter

Borough Park is a dense neighborhood of multigenerational families in attached brick houses on the numbered streets between Fort Hamilton Parkway and McDonald Avenue. Many older residents have been in a Medicaid managed care plan for years, and the “default enrollment” letter shows up when Medicare is about to begin, at 65 or after two years of Social Security disability.

This page is for those residents and for the sons, daughters, in-laws, and home attendants who open the mail with them. It explains what the letter asks, what happens if nobody responds, what changes if you opt out, and which free counselors you can reach. It does not decide anything about anyone’s coverage and it does not enroll anyone.

On Medicare and Medicaid paperwork Borough Park sits in Kings County, the legal name for Brooklyn, and Medicaid is administered citywide by the NYC Human Resources Administration (HRA) rather than a county office. ZIP 11219 covers the core around 13th and 16th Avenues, while 11204 takes in the southern blocks toward Mapleton and Bensonhurst (approximate; verify with USPS). If a form asks for your county, write “Kings.”

Every integrated dual plan open to New York City residents on the state’s 2026 IB-Dual chart lists Kings County, so the plan named on a Borough Park letter covers the address. The practical question is the Medicare network. Maimonides Medical Center on Tenth Avenue anchors care for much of the neighborhood, and the clinics and private practices around it each either are or are not in a given D-SNP’s directory, as is the pharmacy on 13th Avenue where the family fills prescriptions.

In Borough Park several people in one household are often on Medicaid managed care, sometimes with different plans, so first check whose name is on the envelope and what Medicare start date it gives. The notice comes from the plan itself at least 60 days before Medicare begins. If a neighbor on 15th Avenue got one and your mother did not, that is not necessarily an error: not every plan sends a letter.

Opting out means calling or writing the plan; New York Medicaid Choice can connect you. For most people the Medicaid managed care plan ends too and Medicaid continues as fee-for-service. If the person needs more than 120 days of community long-term services, the notice may be the version pointing toward a MAP plan instead of IB-Dual; the NY Medicaid Choice long-term care line at 1-888-401-6582 can explain that path.