The world can be divided into regions based on human and/or physical characteristics. Regions simply refer to spatial areas that share a common feature. There are three types of regions: formal, functional, and vernacular. Formal regions, sometimes called homogeneous regions, have at least one characteristic in common. A map of plant hardiness regions, as in Figure \(\PageIndex\), for example, divides the United States into regions based on average extreme temperatures, showing which areas particular plants will grow well. This isn’t to say that everywhere within a particular region will have the same temperature on a particular day, but rather that in general, a region experiences the same ranges of temperature. Other formal regions might include religious or political affiliation, agricultural crop zones, or ethnicity. Formal regions might also be established by governmental organizations, such as the case with state or provincial boundaries. 
Functional Regions, unlike formal regions, are not homogenous in the sense that they do not share a single cultural or physical characteristic. Rather, functional regions are united by a particular function, often economic. Functional regions are sometimes called nodal regions and have a nodal arrangement, with a core and surrounding nodes. A metropolitan area, for example, often includes a central city and its surrounding suburbs. We tend to think of the area as a “region” not because everyone is the same religion or ethnicity, or has the same political affiliation, but because it functions as a region. Los Angeles, for example, is the second-most populous city in the United States. However, the region of Los Angeles extends far beyond its official city limits as show in Figure \(\PageIndex\). In fact, over 471,000 workers commute into Los Angeles County from the surrounding region every day. Los Angeles, as with all metropolitan areas, functions economically as a single region and is thus considered a functional region. Other examples of functional regions include church parishes, radio station listening areas, and newspaper subscription areas. 
Vernacular regions are not as well-defined as formal or functional regions and are based on people’s perceptions. The southeastern region of the United States is often referred to as “the South,” but where the exact boundary of this region is depends on individual perception (Figure \(\PageIndex\)). Some people might include all of the states that formed the Confederacy during the Civil War. Others might exclude Missouri or Oklahoma. Vernacular regions exist at a variety of scales. In your hometown, there might be a vernacular region called “the west side.” Internationally, regions like the Midlands in Britain or the Swiss Alps are considered vernacular. Similarly “the Middle East” is a vernacular region. It is perceived to exist as a result of religious and ethnic characteristics, but people wouldn’t necessarily agree on which countries to include. Vernacular regions are real in the sense that our perceptions are real, but their boundaries are not uniformly agreed upon. 
As geographers, we can divide the world into a number of different regions based upon formal criteria and functional interaction. However, there is a matter of perception, as well. We might divide the world based on landmasses, since landmasses often share physical and cultural characteristics. Sometimes water connects people more than land, though. In the case of Europe, for example, the Mediterranean Sea historically provided economic and cultural links to the surrounding countries though we consider them to be three separate continents. Creating regions can often be a question of “lumpers and splitters;” who do you lump together and who do you split apart? Do you have fewer regions united by only a couple characteristics, or more regions that share a great deal in common? This text takes a balanced approach to “lumping and splitting,” identifying nine distinct world regions (Figure \(\PageIndex\)). These regions are largely vernacular, however. Where does “Middle” America end and “South” America begin, and why is it combined into a single region? Why is Pakistan, a predominantly Muslim country, characterized as “South” Asia and not “Southwest” Asia? Why is Russia its own region? You might divide the world into entirely different regions, maybe seven based on the continents, or just two: the “core” and the “periphery.” These nine regions are not universally agreed-upon; they are simply foundations for discussing the different areas of the world. 
Furthermore, while it might seem like there are clear boundaries between the world’s regions, in actuality, where two regions meet are zones of gradual transition. These transition zones are marked by gradual spatial change. Moscow, Russia, for example, is quite similar to other areas of Eastern Europe, though they are considered two different regions on the map. Were it not for the Rio Grande and a large border fence dividing the cities of El Paso, Texas and Ciudad Juárez, Mexico, you might not realize that this metropolitan area stretches across two countries and world regions. Even within regions, country borders often mark spaces of gradual transition rather than a stark delineation between two completely different spaces. The border between Peru and Ecuador, for example, is quite relaxed as international borders go and residents of the countries can move freely across the boundary to the towns on either side (Figure \(\PageIndex\)). 
Functional Regions: a region united by a particular function, often economic, sometimes also called nodal regions Transition Zones: an area between two regions that is marked by a gradual spatial change
This page titled 1.6: The World's Regions is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Caitlin Finlayson.
