Updated August 6, 2026. Quick answer: five states still tax what you inherit based on who you were to the person who died, and an unmarried partner lands in the worst class in every one of them — the same class as a stranger, where a spouse pays nothing. Two of the five have a way out, and it is paperwork rather than marriage.
A tax on the relationship, not the estate
An inheritance tax is charged to the recipient and graded by relationship. Spouses are exempt everywhere it exists; children pay little; unrelated people pay the top rate. Legally you are unrelated. Thirty years of cohabitation does not move you a bracket, because none of these statutes has a bracket for it.
The full picture for every state, including the estate taxes that work differently, is on the by-state guide. This page is only the part that changes for partners.
Iowa: the trap that closed
Iowa no longer has one. The Department of Revenue states that “Iowa inheritance tax is not applicable for deaths occurring on or after 1/1/25.” Older writing still lists Iowa among the inheritance-tax states and still warns unmarried partners about its top bracket. For a 2026 death that is simply wrong. The Iowa page has the detail.
New Jersey and Maryland: where registering changes the answer
New Jersey is the most partner-favourable state in the country on this. The Division of Taxation’s beneficiary-class chart lists a civil union partner (after February 19, 2007) and a domestic partner (after July 10, 2004) directly under Class A — the spouse’s class, fully exempt. An unmarried partner who never registered falls to Class D, the unrelated class. The registration is the entire difference between paying nothing and paying the harshest rate the state charges. The New Jersey page covers the classes in full.
Maryland’s carve-out is narrower and has conditions people miss. Against a flat 10% for everyone outside the exempt list, Md. Code Tax-General §7-203(l) exempts a domestic partner on the primary residence — but only where the home was held in joint tenancy with the person who died and passes to the partner, and the partnership is proved, either by the affidavit at Health-General §6-101(b)(1) or by two of the proofs listed at §6-101(b)(2). A separate provision at (l)(3) gives a registered domestic partnership a broader exemption covering all property.
Read the conditions as a checklist, because each one fails independently. Tenants in common instead of joint tenancy: no exemption. No affidavit and only one qualifying proof: no exemption. A partner who assumed the carve-out covered them, and held title the ordinary way, pays the full 10%. The Maryland page has the rest.
Kentucky, Nebraska and Pennsylvania: no relief at all
These three have no partner provision of any kind.
- Pennsylvania charges 15% to other heirs, against 0% for a spouse, 4.5% for children and 12% for siblings. Detail.
- Nebraska charges 15% in its “all others” class with a $25,000 exemption, for deaths on or after January 1, 2023 — better than the 18% and $10,000 that preceded it, and still the top bracket. The statute exempts a spouse outright: “Interests passing to the surviving spouse… shall not be subject to tax.” Detail.
- Kentucky puts an unrelated beneficiary in Class C, graduated from 6% to 16% above a $500 exemption. Class A — which includes a spouse — has been fully exempt since 1998. Detail.
In these three the only levers are the ordinary ones: assets that pass outside the taxable estate where the state allows it, lifetime giving, or life insurance, which is commonly treated differently from a bequest. None of them is a partner exemption, because there is not one to find.
Sources
Iowa Department of Revenue; New Jersey Division of Taxation, Inheritance Tax Beneficiary Classes (N.J.S.A. 54:34-2 governs the classes); Md. Code Tax-General §§7-202, 7-203, 7-204 at the Maryland General Assembly; Neb. Rev. Stat. §§77-2004 and 77-2006 at the Nebraska Legislature; the Kentucky Department of Revenue guide (exemptions at KRS 140.080); the Pennsylvania Department of Revenue. All read 2026-08-06.
Honest gap: we could not verify New Jersey’s Class D percentage rates from a primary source — every official PDF we fetched was scanned or missing — so no Class D number appears above. The classification itself is confirmed. Rates change; check the state before relying on any figure here.
See methodology and corrections. General information about published statutes, not legal advice. No affiliate links, nothing sold.