Urban and peri-urban? Investigation of the location of informal settlements using two databases

Informal settlements are an integral feature of global urbanization, and their future dynamics will impact cities’ development. Current projections of informal settlements’ growth estimate these areas’ expansion, presenting increasing challenges for cities and countries. However, data scarcity on the phenomena of informal settlements impedes answering essential questions on their location, size, and population density that could contribute to a more nuanced understanding of informal growth dynamics. This study combines spatial data from 30 cities’ spatial distribution of informal settlements with the Atlas of Informality, containing 447 neighborhoods, to map the spatial distribution of informal settlements within cities worldwide. In addition, the research locates informal settlements within urban centers to understand the relationship between urban and peri-urban expansion. This exploratory study quantifies informal settlements’ presence and concentration in peri-urban areas. The location mapping reveals that up to 60% of informal settlement areas are in peri-urban zones beyond municipal administrative boundaries. However, this phenomenon differs depending on the world region, albeit the study’s sample size limits current findings. Such insights are highly relevant in influencing policy actions to achieve SDG Target 11.1, as interventions targeted at slums or informal settlements are linked to political and administrative boundaries.