Definition
A mortgage is a security interest in real property (and, in some forms, personal property) granted by a borrower (the mortgagor) to a lender (the mortgagee) as collateral for a debt, typically a loan used to purchase or refinance that property. If the borrower repays the debt according to the agreed terms, the mortgage is discharged and the lender's interest extinguished. If the borrower defaults, the lender may enforce the security interest through foreclosure, ultimately taking title to or forcing a sale of the property.
Two distinct things travel under this name and both appear throughout legal instruments:
1. The security interest itself — the legal relationship created between mortgagor and mortgagee as a matter of property and contract law.
2. The instrument — the written document (deed of trust, mortgage deed, or similar) that creates and evidences that security interest.
Historically, a mortgage operated as an outright conditional conveyance: the lender took legal title to the land, which would revert to the borrower only upon full and timely payment. Equity intervened aggressively to protect borrowers, producing the equity of redemption — the mortgagor's right to reclaim the property by paying the debt even after the legal deadline had passed. Modern mortgage law in the United States has moved away from the title theory in most states, treating the mortgage instead as a lien on property (lien theory), with the mortgagor retaining title throughout.
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Common Language
Modern common usage (Wiktionary): A legal agreement in which a borrower pledges real property as collateral for a loan used to purchase or refinance that property; also, the state of being pledged.
Historical common usage (Webster's 1913): A conveyance of property, upon condition, as security for the payment of a debt or the performance of a duty, and to become void upon payment or performance according to the stipulated terms; also, the written instrument by which the conveyance is made.
Editorial note: The common understanding of mortgage — as a home loan — collapses the distinction between the loan obligation itself and the security instrument that backs it. In legal practice and research, these are separate documents with separate legal consequences. A borrower signs both a promissory note (the debt) and a mortgage or deed of trust (the security); the two are not interchangeable. Researchers working with historical sources should also note that the Webster's 1913 definition reflects the older title-theory framework, treating a mortgage as a conveyance rather than a lien — a framing that will appear throughout 19th-century cases and treatises but does not accurately describe how most U.S. jurisdictions treat mortgages today.
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Common Confusion
MORTGAGE vs. DEED OF TRUST: In many states, the functional equivalent of a mortgage is a deed of trust, in which the borrower conveys title to a neutral third-party trustee (not the lender) to hold during the loan term. The practical distinction matters most at foreclosure: deeds of trust commonly permit non-judicial foreclosure (faster and cheaper), while traditional mortgages may require judicial proceedings. Researchers encountering "deed of trust" in sources from Texas, California, Virginia, and other deed-of-trust states should not assume the term is synonymous with mortgage in every procedural respect.
MORTGAGE vs. PROMISSORY NOTE: The mortgage secures the debt; the note is the debt. A lender who holds the note but not the mortgage (or vice versa) may face serious enforcement problems. The split-the-note problem became prominent in litigation following the post-2008 foreclosure crisis and generated a substantial body of case law.
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Core Elements
For a valid mortgage, the following elements are generally required:
1. A debt or obligation to be secured — the mortgage has no independent existence; it is accessory to an underlying obligation.
2. An intent to create a security interest — the instrument must be intended as security, not as an outright conveyance. The equitable maxim "once a mortgage, always a mortgage" prevents parties from converting a mortgage into an absolute deed by subsequent agreement.
3. A mortgagor with sufficient interest in the property — one cannot mortgage more than one holds.
4. A mortgagee capable of holding the security interest.
5. A written instrument satisfying the Statute of Frauds — oral mortgages on real property are generally unenforceable, though equity may impose a constructive trust in extreme cases.
6. Delivery and (for real property) recording — recording is not required for the mortgage to be valid between the parties, but an unrecorded mortgage is typically subordinate to subsequent bona fide purchasers and lien creditors who record first.
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Recognized Forms
/SUBTYPES
Purchase Money Mortgage: A mortgage given by the buyer to the seller (or to a third-party lender) at the time of conveyance to secure the unpaid purchase price of the property conveyed. Historically significant because purchase money mortgages often carry priority over other liens, including those that attached to the buyer before the purchase.
Reverse Mortgage (HECM): A mortgage product available to older homeowners in which the lender makes payments to the borrower against the equity in the home, with repayment deferred until the borrower sells, moves, or dies. Governed by federal rules under the Home Equity Conversion Mortgage program. See Encyclopedia entry: Mortgages — Reverse Mortgages (HECM).
Equitable Mortgage: A transaction that, though not formally structured as a mortgage, is treated by equity courts as one — typically because the parties' intent was to create a security arrangement. Appears frequently in older equity decisions.
Chattel Mortgage: A mortgage on personal property rather than real estate. Largely superseded in the United States by Article 9 of the Uniform Commercial Code, which governs security interests in personal property, but the term and its framework appear throughout pre-UCC sources.
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Why It Matters in Research
The legal structure of a mortgage shifted substantially during the 19th and 20th centuries, and that shift is invisible in many historical dictionary entries. Sources from before approximately 1900 — including Blackstone, Kent's Commentaries, and the early editions of Washburn on Real Property cited in Black's — operate primarily within the title-theory framework. Courts in those sources discuss the mortgagee as the legal owner of the land. Modern researchers applying those sources to contemporary lien-theory jurisdictions will misread both the doctrine and the cases.
The equity of redemption is indispensable context for any historical mortgage research. Equity's intervention — refusing to enforce strict forfeiture clauses, recognizing the mortgagor's right to redeem after the law day had passed — is the reason foreclosure exists as a distinct proceeding. "Foreclosure" originally meant the foreclosing (cutting off) of the equity of redemption. Researchers who encounter foreclosure proceedings in 18th- and 19th-century equity records must understand this conceptual baseline or the proceedings will make little sense.
Priority questions are among the most litigation-dense areas of mortgage law. Recording acts (race, notice, race-notice) determine priority among competing claimants, and the rules vary by state. When working with historical title abstracts or multi-lender disputes, consult the Encyclopedia entry on Priority of Mortgages and Subordination Agreements before assuming any default priority rule applies.
Mortgage fraud has become a substantial area of criminal and civil liability, generating its own documentary record — FBI reports, HUD guidance, state attorney general enforcement actions — that researchers may need to integrate with property records and loan documents. See Encyclopedia entry: Mortgages — Mortgage Fraud.
The deed of trust states pose a particular trap: West Coast and Southern sources will use "deed of trust" where Eastern sources say "mortgage." The legal consequences are not always identical, especially regarding foreclosure procedure and deficiency judgments. A corpus search for "mortgage" in California sources should be supplemented with searches for "deed of trust."
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Historical Dictionary Support
The historical dictionaries substantially agree on the classical definition. Black's (1st ed.) tracks Washburn's formulation almost verbatim: an estate created by a conveyance absolute in form, intended to secure performance, becoming void upon performance. Rapalje & Lawrence confirm that while real property and leaseholds are the most common subjects, personal property may also be mortgaged — a point that becomes important when tracing the lineage of chattel mortgages into modern secured transactions law.
What the historical dictionaries largely omit is the lien theory and its implications. By the time Black's 1st edition appeared (1891), the lien-theory/title-theory split was already shaping American case law, but the dictionary definition continued to lead with the conditional conveyance framing. Researchers relying solely on these definitions will not find clear guidance on when American courts began consistently treating the mortgage as a lien rather than a transfer of title — that evolution must be traced through treatises (Wiltsie on Mortgage Foreclosure, Jones on Mortgages) and state case law.
The maxim "once a mortgage, always a mortgage" appears in Black's and has genuine doctrinal force: equity will look past formal labels to determine whether a transaction is in substance a security arrangement, and if it is, will treat it as a mortgage regardless of what the instrument says. This remains good law and is a live issue in litigation over sale-leaseback transactions and deeds given in lieu of foreclosure.
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Jurisdictional Note
The United States divides broadly between title-theory states (where the mortgagee holds legal title during the loan term) and lien-theory states (where the mortgagor retains title and the mortgagee holds only a lien). A smaller group of intermediate-theory states adopt a hybrid. This division drives significant differences in the mortgagee's right to possession before foreclosure, the availability of rents and profits, and deficiency judgment procedures. Researchers should identify which theory governs before applying any doctrine derived from a specific state's cases or statutes to another jurisdiction.
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Encyclopedia Cross-Reference
Mortgages — Mortgage Fraud (The Law Mind Property Law Encyclopedia)
Mortgages — Reverse Mortgages (HECM) (The Law Mind Property Law Encyclopedia)
Mortgages — Priority of Mortgages and Subordination Agreements (The Law Mind Property Law Encyclopedia)
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