See IRS Publication 523 Selling Your Home page 10 - https://www.irs.gov/pub/irs-pdf/p523.pdf#page=10
Home Inherited
Home acquired from a decedent who died before or after 2010. If you inherited your home from a decedent who died before or after 2010, your basis is the fair market value of the property on the date of the decedent's death (or the later alternate valuation date chosen by the personal representative of the estate). If an estate tax return was filed or required to be filed, the value of the property listed on the estate tax return is your basis. If a federal estate tax return didn’t have to be filed, your basis in the home is the same as its appraised value at the date of death, for purposes of state inheritance or transmission taxes.
