Definition
A valley, in legal contexts, refers to the lowland terrain lying between ranges of hills or mountains, including the bed of a stream and adjacent alluvial plains. The term appears most frequently in land grant interpretation, public land surveys, mining law, property boundary disputes, and water rights litigation, where the precise geographic extent of a "valley" determines what land was conveyed, claimed, or regulated.
Legal usage does not impose a single technical definition. Courts have generally deferred to the common geographic understanding of the word as applied to the specific terrain at issue, treating it as a term of description rather than a term of art.
Common Language
Modern common usage (Wiktionary): An elongated depression cast between hills or mountains, often with a river flowing through it; also, any area draining into a river, or a structure resembling such a depression (e.g., the interior angle of two sloping roof planes).
Historical common usage (Webster's 1913): The space enclosed between ranges of hills or mountains; the strip of land at the bottom of depressions intersecting a country, including usually the bed of a stream, with frequently broad alluvial plains on one or both sides.
The legal meaning does not sharply depart from the common geographic meaning — courts have largely adopted the lay understanding. The research gap is not semantic divergence but geographic specificity: in a legal dispute, what counts as "the valley" is a fact question about the actual terrain, not a stable definitional category. A document conveying land "in the valley" may or may not include adjacent slopes, alluvial benches, or tributary drainages, and that ambiguity is where legal interpretation does its work.
Why It Matters in Research
Researchers encounter "valley" most often in three contexts, each with distinct interpretive stakes.
First, in land grant and patent interpretation — particularly Spanish and Mexican grants in the American West and Southwest — "valley" language in original grants was frequently used as descriptive shorthand for large swaths of terrain. When those grants were later litigated before the U.S. Land Commission or federal courts, the word's geographic extent became dispositive. Sources from the mid-nineteenth century onward reflect courts struggling to reconcile imprecise Spanish-language survey language with Anglo-American conveyancing standards.
Second, in mining law, "valley claims" and the distinction between valley placers and hillside or bench placers carried real legal significance. The elevation and character of the ground — valley floor versus mountain slope — could determine what type of claim applied and what proof of discovery was required.
Third, in water rights and prior appropriation doctrine, "valley" terminology appears in irrigation statutes, watershed designations, and adjudication decrees. An appropriator's right might be described as applying to "waters of the [X] valley," and the geographic scope of that phrase affects who else may claim from the same system.
A significant research trap: historical survey documents, land office records, and early federal court opinions often used "valley" loosely and interchangeably with "canyon," "draw," "basin," and "bottom." Do not assume terminological consistency across documents from the same period or the same litigation.
The Bouvier entry's citation to 167 Fed. 669 anchors the definition in mountainous-country usage specifically. Researchers should note that this framing — valley as lowlands in contradistinction to slopes and ridges — reflects a western U.S. interpretive context. In eastern cases involving gentler terrain, courts may apply a broader conception without distinguishing sharply between valley floor and surrounding upland.
Historical Dictionary Support
Bouvier's offers a brief but pointed entry: valley means lowlands as distinguished from mountain slopes and ridges, citing a federal reporter case for authority. This is less a formal legal definition than a judicial gloss adopted in a specific factual context.
The entry is useful primarily as confirmation that courts treated the common geographic meaning as controlling, rather than developing a specialized legal definition. Bouvier does not address alluvial plains, tributary drainages, or the upper limits of valley terrain — all of which have been contested in actual litigation.
Webster's 1913 is more expansive and, for historical research purposes, more useful as a baseline for what courts and conveyancers in the late nineteenth century would have understood the word to mean when they used it in instruments and statutes. The Webster's formulation — including the stream bed and broad alluvial plains on one or both sides — aligns well with the practical concerns of western water and land law.
Neither source addresses the roof valley (the interior angle of intersecting slopes), which is a construction and property law usage of the term with no meaningful intersection with these historical dictionary treatments.
Jurisdictional Note
The legal significance of "valley" as a geographic descriptor is most pronounced in western states with public land survey histories, prior appropriation water systems, and Spanish or Mexican land grant legacies. Eastern jurisdictions encounter the term less frequently as a term requiring legal interpretation.