Usucapio (from the Latin usus, use, and capire, take) is a concept from Roman law by which a title or right to property is acquired through uninterrupted and undisputed possession for a prescribed term. It is commonly found in Romance-language jurisdictions with civil law systems – Spain and the Spanish-speaking countries, Portugal and Brazil, France, and Italy, where the respective terms are usucapión in Spanish, usucapão in Portuguese, usucapion in French, and usucapione in Italian. 

Usucapio and its descendants overlap in various respects with common-law adverse possession. However, as we shall see, the differences between both concepts are such that they cannot be equated, and the translation of usucapio as “usucaption” or “usucapion”, overliteral though it may seem to be, is preferred.

Usucaption and adverse possession are similar in that they are both legal figures that recognize long-term possession of an asset – most frequently, real estate – as ownership. However, their respective purposes differ. The goal for usucaption is to provide legal security, especially when formal transfer methods were not followed despite long occupancy: for this reason, it is often sometimes referred to as “acquisitive prescription”, in reference to the period of time after which possession is acquired.

By contrast, common-law adverse possession is intended to encourage the productive use of properties (usually land) by granting title to those who actively use it, often resolving disputes over neglected properties. In adverse possession, the focus is on physical possession of the property, which must be open, notorious, hostile – that is, without the owner’s permission – and exclusive: hence its sometimes being referred to as “squatters’ rights”.

Two examples might help grasp the conceptual difference between usucaption and adverse possession. 

In a lawsuit in Spain, a woman had publicly held three rural properties and one urban property, in the capacity of owner, with no interruptions or disputes, for 47 years. She filed a claim to acquire legal ownership over those properties through their use. 

In Spain, as in other civil law jurisdictions, two categories of usucaption are distinguished: ordinary usucaption, in which the party who seeks to have their ownership recognized acted in good faith and has a just title; and extraordinary usucaption, in which neither good faith nor just title are required. In our Spanish example, the woman was aware that she was not the legitimate owner of the properties – the previous owner had died intestate and no heirs had claimed them. However, because a period longer than the 30 years required for extraordinary usucaption had elapsed, the courts awarded her legal ownership over the properties.

Adverse possession can be illustrated by the British case Thorpe v Frank (2019). In 1986, one Mrs Thorpe paved a triangular plot of land belonging to her neighbours, maintained it – power-washing the area, clearing the area of litter, and weeding it, among other tasks – and parked her car there, yet did not fence the area. In 2012 Mr and Mrs Frank acquired the property.

In 2013, Mrs Thorpe fenced the paved area and applied for registration as the owner. Mr and Mrs Frank objected, and the Court held that although fencing the land would have been the clearest way to demonstrate possession, Mrs Thorpe had nevertheless demonstrated the typical actions of an owner for a sufficient period of time, which were sufficient to interfere with the ownership of Mr and Mrs Frank. Therefore, the Court upheld Mrs Thorpe’s entitlement to registration as the land owner.

Notice the difference in the basis for the award of ownership. In the case of Spanish usucapión, ownership was acquired because the claimant had publicly held the properties, with no interruption or dispute, for the very long period of time required. By contrast, in English adverse possession, although time was also a factor, emphasis was placed rather on the fact that Mrs Thorpe had treated the property, which was otherwise neglected by its original owners, as its owner through her actions. 

These examples, again, illustrate the differing purposes of usucapio and adverse possession: for the former, providing legal security in cases of long occupancy; for the latter, acknowledging the right acquired through active use.