Definition
An action of Roman civil law for the settlement and ascertainment of disputed boundaries between adjacent landowners. The finium regundorum actio lay between persons whose estates shared a common border (qui confines agros habent) when the precise location of that boundary was in contest. The action empowered the presiding judge (judex) not merely to declare rights but to adjudicate the boundary itself — assigning to each party the land determined to belong to them.
The action was not purely declaratory. It carried the power of allocation, meaning the judex could redistribute a strip of contested land between the parties rather than simply confirm an existing line. This distinguishes it from a simple possessory or ownership action.
Why It Matters in Research
Researchers will encounter this term primarily in works on Roman law, civil law jurisdictions derived from Roman tradition, and in historical treatises bridging Roman and common law property doctrine. Its significance lies in its procedural structure as much as its substantive purpose.
The term appears almost exclusively in Latin in primary and historical secondary sources. Researchers reading early modern civil law commentators, or 19th-century American treatises engaging with civilian doctrine, should expect the term in untranslated form. Bouvier reduces it to a single-sentence entry, which understates the procedural complexity that Rapalje & Lawrence and Burrill preserve.
The most important research trap is conflating this action with a simple trespass or ejectment action in the common law tradition. The finium regundorum actio was not about wrongful entry or dispossession — it was specifically about boundary uncertainty between neighbors with adjacent estates. The remedy was adjudicative allocation, not damages or restoration of possession.
Researchers tracing the influence of Roman law on American and English property law will find this action relevant to discussions of boundary dispute doctrine, the office of the surveyor, and early equity jurisdiction over property lines. The civilian tradition's willingness to give the judge power to draw (or redraw) a boundary — rather than simply declare who was right — contrasts with the common law's historical preference for jury-determined fact questions about boundary locations.
For corpus researchers working in the Law Mind collection: this term appears in civil law treatises and in comparative law discussions more often than in case reporters. When it does appear in American sources, it is typically illustrative of a civilian doctrine being contrasted with a common law rule, not applied directly.
Historical Dictionary Support
The four source dictionaries are in close agreement on the basic definition — an action between adjacent landowners to settle disputed boundaries — but vary in the depth of procedural detail they supply.
Burrill provides the most substantive entry, identifying the parties (qui confines agros habent), supplying primary source references to the Institutes and Digest, and cross-referencing Mackeldey. This makes Burrill the most useful starting point for researchers who need to locate the original civilian authorities.
Rapalje & Lawrence contributes the most analytically important detail: the observation that the finium regundorum actio was one of only three Roman law actions in which the adjudicatio appeared in the formula. The adjudicatio was the clause by which the judex formally assigned shares or parcels to the respective parties — a procedural power broader than simple declaration. The other two actions sharing this feature were the actio familiae erciscundae (for partition of an inheritance) and the actio communi dividundo (for partition of common property). This tripartite grouping is analytically significant and is missed entirely by Bouvier and compressed out of Black's truncated entry.
Black's second edition entry is visibly incomplete — the definition cuts off mid-phrase ("Action for regulating bound—") — suggesting a printing truncation. Researchers relying solely on Black's for this term will find it inadequate.
What the historical dictionaries do not address: the question of how, or whether, civilian boundary-adjustment doctrine influenced American equity courts in boundary dispute cases. That gap must be filled from treatise literature rather than the dictionary shelf.
Jurisdictional Note
This action belongs to Roman civil law and has no direct analog in Anglo-American common law. Its doctrinal descendants appear in jurisdictions with civilian or mixed legal traditions — Louisiana, Quebec, South Africa, and the civil law systems of continental Europe — where boundary adjustment actions remain cognizable. Common law jurisdictions addressed boundary disputes through trespass, ejectment, and ultimately equity, without adopting the adjudicatio mechanism.