I received an inheritance of $103,000 from my cousin who had lived in Ireland. Do I have to report this on my tax return?

No. Inheritances of any amount from decedents in any location are fully tax free. However, if an inheritance is considered to be “income in respect of a decedent,” which is income earned by the decedent on which no income taxes had yet been paid, then you pick up the income when and to the extent you receive it. For example, if you inherited an IRA that had been funded with tax-deductible contributions, then the inheritance isn’t taxed, but any distributions from the IRA would be ordinary income to you.