and border gateway states that also have overall large populations—of both the native born and immigrants. When mapping international immigrants as a proportion of the total population, the states of Nevada, New Jersey, and Massachusetts also stand out, with over 15 percent of their populations being foreign born (figures 3.8 and 3.9).
Figure 3.7.US population with and without immigration. Without immigrants and their children, it is estimated that the US population would have had 72 million fewer people in 2015. Data source: Pew Research Center, 2015.
Native-born migrants within the United States continue to move to the Sun Belt states. The largest native-born migrant stock is found, starting with the highest proportion, in Florida, California, and Texas, followed by Georgia, North Carolina, and Arizona.
Figure 3.8.Proportion of foreign-born residents, 2014. States with more immigrants represent demographic changes that will be faced by the country as a whole. Explore the map at http://arcg.is/2dDtVJc. Data source: US Census.
Figure 3.9.Tet Lunar New Year celebration in Little Saigon, Westminster, California. Gateway states such as California, Texas, New York, and Florida have large immigrant populations. The United States as a whole is becoming more diverse due to immigration. Photo by Joseph Sohm. Stock photo ID: 297524915. Shutterstock.
Figure 3.10 shows the movement of native-born Americans by region. Generally, people stay within the region where they were born—a clear sign of distance decay—so those born in the West tend to move to other western states, while those born in the Midwest stay within their own region as well. The same holds true for people born in the South and Northeast. However, it can also be seen that when people leave their region of birth, there are clear migration flows to the Sun Belt—California, Texas, and Florida stand out as having large numbers of immigrants from all four major US regions.
Figure 3.10.State of origin for US domestic migrants. Distance decay is evident in that people tend to move between states within the same region. Explore the data in ArcGIS Online at https://arcg.is/1ymjTa. Data source: US Census.
Go to ArcGIS Online to complete exercise 3.1: “Spatial distributions.”
Push and pull forces
As seen in the previous section, some places clearly attract immigrants, while other places induce emigration. To understand the driving forces behind these patterns, it is essential to look at the place-specific characteristics of sending and receiving locations as well as the spatial interaction that ties places together.
Different theories have been given to help explain how, where, and why people migrate. One of the first and most influential thinkers on migration was E. G. Ravenstein, who in 1885 wrote On the Laws of Migration. He presented a set of “laws” based on his research in Great Britain in the nineteenth century. While some of his laws do not apply to all contemporary migration trends, many still inform modern migration theory. Ravenstein’s laws of migration are as follows:
•Migrants move short distances along fixed currents toward “great centers of commerce and industry.”
•Rapidly growing cities absorb migrants from nearby places. The places vacated by these migrants are then filled by migrants from places farther away, in a step-by-step fashion. Communication flows between places can countervail the disadvantages of distance.
•Some places see a dispersion of their populations, as they migrate to growing urban areas.
•All migration currents have a compensating countercurrent.
•Long-distance migrants generally move to one of the great centers of commerce or industry.
•Rural residents migrate more than urban residents.
•Females migrate more than males.
Implicit in Ravenstein’s work is the idea that certain places attract immigrants, as in his “great centers of commerce and industry.” The idea that some places attract people led other migration researchers to expand on the idea of push and pull factors. These theories are based on the fact that places of origin have factors that “push” people to leave, while places of destination have factors that “pull” people to come. These forces can be viewed in terms of the economic, social and cultural, political, and environmental conditions of places.
Ravenstein also noted that migration is not random but rather is tied to currents of migration—flows between specific places that people follow in regular patterns. This spatial interaction between places is fed by communication, as people share information on the opportunities and challenges involved with making the move. Furthermore, he noted that the characteristics of migrants take a specific form. Migrants are not randomly selected from the general population but tend to have specific characteristics in terms of sex, age, income, and other variables.
Economic push and pull
As you may expect, some of the most common reasons to migrate are economic. One way of understanding how economic forces influence migration is through neoclassical migration theory. This theory focuses on wage differentials between origin and destination. If wages are low in one place relative to another place, then individuals will be pushed from the low-wage to the high-wage location. This theory is useful in understanding much migration, in that historically and globally, economic forces are the key drivers of migration.
For example, most migration from Mexico to the United States has been driven by significant wage differences between the two countries. The average Mexican income in 2014 was US $12,850, adjusted for cost of living differences with the United States. This compares to average US earnings of $57,000. But neither most Mexicans nor most Americans earn the average income. In 2014, 14.8 percent of Mexican workers earned less than two-thirds of the median wage, the equivalent of US $707 or less per month, again accounting for differences in cost of living. Those making only the minimum wage earned less than US $160 per month. By migrating to the US and earning the 2014 federal minimum wage of $7.25 per hour, a full-time worker would earn about $1,160 per month. That is a 60 to 600 percent increase in wages—certainly enough of an incentive for many to migrate. The gains are even greater for immigrants who arrive in states with minimum wages above the federal level. For instance, the 2014 minimum wage in California was $9 per hour, while in Illinois it was $8.25 and in New York, $8.
But wages alone are not enough to explain all migration patterns. Economic forces can also include unemployment rates, working conditions, and opportunities for career advancement. Places with high unemployment rates are likely to push people away, while places with low unemployment will pull people in. Similarly, a place with a cluster of large corporations in a specific industry may offer attractive benefits packages, interesting coworkers, and opportunities to move into positions of greater responsibility. The technology cluster in Silicon Valley, for instance, pulls in people from all over the US and the world for good wages but also for fun and interesting work and myriad opportunities for professional growth. Likewise, people migrate from around the world to New York and London because of ample career opportunities in their financial sectors.
The level of emigration from a place can also be related to level of economic
