Peri-urban space is the geographical space that occupies the interstitial space left free by the urban space within an urban agglomeration. There is no definition accepted by all of what is understood as a peri-urban space, and when it stops being so and becomes an urban space.

Periurbano is a term that is not part of the dictionary of the Royal Spanish Academy (RAE, 22nd edition, published in 2001). But it has been used since the late 70s, originally in France. In Spanish, it began to be used with the research directed by the Spanish sociologists Mario Gaviria and Artemio Baigorri in the Metropolitan Area of ​​Madrid, between 1982[1]​ and 1984.[2]​ In that project, an entire public action program was proposed to regenerate the peri-urban space of Madrid by developing agrarian, leisure, use planning policies, etc.[3]​.

The peri-urban space is a space that is defined by indefinition: it is not a field, nor is it a city. It refers to an interface situation between two apparently well-differentiated geographical types: the countryside and the city. It is difficult to conceptually define and delimit, it has the disadvantage that it is a “slippery” territory, in a transitional situation, in permanent transformation (or with expectations of being transformed), fragile, susceptible to new interventions. With the passage of time, the peri-urban “extends”, “relocates”, “moves from place to place”. It is a territory in consolidation, quite unstable in terms of the constitution of social networks and great heterogeneity in land uses.

González Urruela (1987) carried out a review of the history of the peri-urban area, highlighting the problems that this diverse space generated for the narrow disciplines, thus generating in each of them the need for denominations that allow them to address it. The points in common that all disciplines had for this territory, according to the author, are three: firstly, its morphological individuality or its morphologically mixed character; secondly, the more lax type of occupation as opposed to the urban one; Thirdly, the link with the city, in relation to local productions and services.

Other close and associated concepts:

The process of peri-urbanization in Latin America has its own characteristics, different from those of most European countries. The process is strongly marked by the heterogeneity of social agents and spatial processes, with high mobility and impact on the play of forces that build the territory.[7]​.