Deeds
County recorder or title company can confirm liens; probate or trust deed transfers follow state recording rules
Some steps differ by region inside the country.
Where
The county recorder or register of deeds for the county where the property sits. Most now have searchable online records.
How
Search the county recorder's online records by their name to find every property recorded in it.
Read the most recent deed to see exactly how title is held, since that determines what happens on death.
Check for any transfer on death deed, which several states allow and which bypasses probate.
Search in every county and state where they may have owned property, including vacation and inherited land.
What to bring
The property address or parcel number
A certified copy of the death certificate
Letters testamentary for any transfer
This is practical information, not legal, medical, or financial advice.