Definition
Tacking is a doctrine with two distinct applications in property law: one in adverse possession and one in mortgage priority.
1. Adverse Possession (Tacking of Periods). A claimant seeking to establish title by adverse possession may add — "tack" — their own period of open, hostile, and continuous possession to that of a prior possessor, provided there is privity of possession between them. This allows a claimant who has not personally satisfied the full statutory limitations period to meet the requirement by combining successive periods of qualifying possession. Without tacking, each possessor would have to restart the clock independently.
2. Mortgage Priority (Tacking of Securities). In equity, a mortgagee holding both a first lien and a third lien may "tack" the third to the first, forcing an intermediate second mortgagee — who seeks to redeem the first mortgage — to also discharge the third. The doctrine prevents a junior interest-holder from selectively redeeming only the encumbrances that benefit them while bypassing others held by the same creditor. It operates as a shield for the senior lienholder who has acquired a subsequent security without notice of an intervening interest.
Common Language
Modern common usage (Wiktionary): Present participle of "tack" — to change direction, as a sailing vessel, or to attach something loosely.
Historical common usage (Webster's 1913): "A union of securities given at different times, all of which must be redeemed before an intermediate purchaser can interpose his claim." (Webster's 1913 here borrows directly from Bouvier, reproducing the mortgage definition rather than a general usage.)
The common sailing sense — changing course or pinning something temporarily — carries a faint metaphorical echo into legal usage (joining things together, attaching periods or securities), but the legal doctrine is substantively distinct. Researchers encountering "tacking" in historical equity pleadings or land records should not import any ordinary meaning; the term operates as a precise term of art in both its legal contexts.
Recognized Forms
/SUBTYPES
1. Tacking in Adverse Possession. The joining of successive possessory periods by parties in privity (grantor-grantee, devisor-devisee, or analogous transferor-transferee relationship). Most U.S. jurisdictions require privity; a mere stranger cannot tack to a prior adverse possessor's period.
2. Tacking of Mortgages (English Doctrine). The merging of a first and third mortgage by a single holder to defeat a second mortgagee's right of selective redemption. This doctrine was fully developed in English equity and never gained widespread adoption in American law.
Why It Matters in Research
Researchers face two distinct hazards with this term. First, conflation: historical sources almost exclusively define tacking in its mortgage sense, yet modern American research encounters the term overwhelmingly in the adverse possession context. A researcher reading nineteenth-century dictionary entries or English equity treatises will find mortgage tacking foregrounded and adverse possession tacking treated briefly or omitted. The proportions are essentially reversed in modern American case law and scholarship.
Second, jurisdictional obsolescence: the mortgage tacking doctrine was largely abrogated or displaced in England by the Land Transfer Act 1875 and subsequent recording legislation. American jurisdictions, operating under recording acts from an early date, generally rejected the doctrine on the ground that a bona fide purchaser's protection under the recording system made the equitable mechanism unnecessary or contrary to public policy. Researchers finding references to tacking in pre-1875 English equity sources — including Story's Equity Jurisprudence and Jeremy's Equity Jurisdiction, both cited in the historical dictionaries — should treat that doctrine as largely obsolete for American purposes and as partially displaced in English law.
For adverse possession research, the privity requirement for tacking is the critical variable. Primary sources, including deeds, wills, and probate records, become essential evidence to establish the chain of privity justifying the tack. The Law Mind Property Law Encyclopedia entry on adverse possession covers this dimension directly.
Corpus researchers should also note that "tacking" sometimes appears in insurance law literature to describe the attachment of riders or endorsements, and in legislative history in reference to unrelated provisions added to bills. Neither usage is the legal doctrine described here.
Historical Dictionary Support
The historical dictionaries speak almost in unison on tacking, all adopting substantially the same language drawn from Story's Equity Jurisprudence (§ 412) and, to a lesser extent, Jeremy's Equity Jurisprudence. Black's (both editions), Bouvier, Burrill, and Anderson all lead with the mortgage priority definition, presenting it as the primary or sole legal meaning. This uniformity reflects the English equity origins of the term and the dominance of chancery practice in the period when these dictionaries were compiled.
Anderson's dictionary provides the most instructive illustration: three successive mortgagees, with the first holding legal title and the others holding only equitable interests. Anderson walks through how the first mortgagee, having purchased the third mortgage without notice of the second, can require the second mortgagee to redeem both before asserting priority. This is the clearest explanatory treatment in the historical sources.
What the historical dictionaries collectively miss is the adverse possession application, which had developed in both English and American courts by the mid-nineteenth century but receives little or no treatment in these sources. Burrill's entry gestures toward the mortgage context being the term's primary home ("the term tacking in English law is particularly applied to mortgages"), which implicitly acknowledges other applications without naming them. Researchers relying solely on historical dictionary entries would have an incomplete and potentially misleading picture of how the term functions in modern American law.
Rapalje & Lawrence's entry under this heading addresses notice doctrine rather than tacking directly — likely a misfiled or cross-reference entry — and should not be relied upon for substantive tacking doctrine.
Jurisdictional Note
Mortgage tacking was a creature of English equity that did not transplant successfully to most American jurisdictions, where recording acts provided the framework for resolving priority disputes. Adverse possession tacking is recognized across U.S. jurisdictions but varies on the privity requirement: most states require privity of possession to tack, but the strictness of that requirement and what relationships satisfy it differ by state.
Encyclopedia Cross-Reference
Adverse Possession — Tacking of Successive Possessors (The Law Mind Property Law Encyclopedia).