Definition
An official register or statement documenting the quantity and value of real property, prepared for purposes of taxation. The term derives from French law and functions as a variant spelling of *cadastre*. A cadastu is, in essence, a formal governmental inventory of land: it records parcels, their physical extent, and their assessed value, providing the fiscal baseline from which property tax obligations are calculated.
The term appears in older Anglo-American legal dictionaries primarily as a transliteration of the French administrative concept, not as an independently operative term in common law systems.
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Common Confusion
CADASTU, CADASTRE, and CATASTO are variant spellings and cognates of the same underlying concept. Researchers encountering *cadastu* in historical sources should treat it as equivalent to *cadastre*. The spelling *cadastu* is the less common form; *cadastre* is the standard English and modern French spelling. Neither should be confused with a *cartulary* (a register of title deeds) or an *extenta* (a medieval survey of manorial property), which serve overlapping but distinct documentary functions.
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Why It Matters in Research
The primary research trap with *cadastu* is its near-total absence from American and English primary legal sources. The term appears in Black's Law Dictionary as a cross-reference vehicle — both editions immediately redirect researchers to *cadastre* — rather than as a freestanding operative legal term. A researcher who locates *cadastu* in a historical source is almost certainly reading a French-law discussion or a treatise that draws on civilian or Continental property concepts.
For corpus researchers, this matters in two ways. First, any document using *cadastu* (rather than *cadastre*) is likely pre-twentieth century and may reflect a looser transliteration practice common in nineteenth-century American legal writing on comparative or civil law topics. Second, because Black's treats the two spellings as interchangeable, searches limited to one spelling will miss documents using the other.
The concept itself — a state-maintained record of land parcels and their values for tax purposes — is historically significant in jurisdictions with civil law roots. Louisiana, with its French and Spanish legal heritage, and territories acquired through the Louisiana Purchase were subject to cadastral survey systems that left archival traces still relevant to title research. Researchers working on land grants, Spanish or French colonial property claims, or early American public land administration may encounter cadastral records as primary sources, not merely dictionary entries.
The cadastral function is also the ancestor of modern property tax assessment rolls and, in many countries, the land registry. The conceptual line from *cadastu* to a modern county assessor's parcel map is direct.
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Historical Dictionary Support
Both Black's Law Dictionary (1st Ed.) and Black's Law Dictionary (2nd Ed.) give identical, terse treatment: "In French law. An official statement of the quantity and value of realty made for purposes of taxation; same as cadastre." The cross-reference is the entire entry. Neither edition elaborates on the procedural mechanics of a cadastu, its evidentiary weight, or its relationship to systems outside France.
The historical dictionaries agree completely, which reflects the term's status as a borrowed concept rather than a developed common law doctrine. What the dictionaries miss is context: they do not note the practical relevance of cadastral records to American land history, the role of the cadastral system in Napoleonic administrative reform, or the distinction between a cadastu (a valuation and quantity record) and a land title registry (which records ownership). For researchers, that silence is significant — the dictionaries were flagging the term for completeness, not because it had independent doctrinal weight in Anglo-American practice.
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Jurisdictional Note
The term has no independent operative force in American or English common law. Its legal relevance in the United States is largely historical, arising in the context of French colonial land administration and the civil law jurisdictions of Louisiana and former Spanish territories. Modern cadastral concepts persist in property tax assessment and public land survey systems but are no longer described using this term.
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