In the broadest sense of the word, ‘landscape’ is the result of the interaction between human society and the natural environment.
In order to understand the complex relationships between the different physical, biological, and cultural components that affect the region the Atlas studies, we have divided the region into different landscape units.

In terms of the natural features found in the region, there are four main landscape units:

Pampa: the plains of the Pampa
Coast: the coastal strip
Delta: the lower Paraná river delta
River: the River Plate estuary

Both the river and the delta are fundamentally natural environments. In contrast, the Pampa and the coast are complex landscape units because urbanization has profoundly changed their original forms. The Area Metropolitana de Buenos Aires (AMBA; Buenos Aires Metropolitan Area) extends over part of the Pampa and coast, and is another landscape unit.

The Atlas thus has five landscape units:

- AMBA (Area Metropolitana de Buenos Aires, Buenos Aires Metropolitan Area) the urbanized part of the Pampa and coastal strip.
- PAMPA the plains of the Pampa (excluding urbanized areas)
- COAST the coastal strip (excluding urbanized areas)
- DELTA the lower Paraná river delta
- RIVER the Rio de la Plata estuary

It should be pointed out that the line separating the AMBA from the Pampa is arbitrary, and constantly changes position. The transitional area between the two is usually referred to as an “urban perimeter” area, and displays a mix of rural and urban phenomena.