If a relative has several mortgages over time on a piece of property, it can be tempting to gloss over them as not really being as genealogically relevant as other documents. That can be a mistake. Sometimes the lenders or the holders of the note are not a financial institution or an individual who makes their living loaning money.
Sometimes they are relatives. Always give a little time to see from whom your ancestor borrowed money. This illustration is from an 1879 trust deed where the husband and wife borrowing money against their farm are borrowing it from the wife’s mother and step-father.
Those relationships are not stated in the record and usually are not stated in the record. The legal agreement is about who owes money to whom, how much money is owed, the item put up as collateral, the terms of repayment, etc.
Remember that in the United States real estate mortgages are usually filed in the same office as the land deeds since their existence impacts property titles.