At its founding, the United States was an overwhelmingly rural nation. The inaugural census of 1790 showed that 95% of all Americans either lived in isolated rural areas, on farms, or in tiny towns with fewer than 2,500 people. However, a steady national trend toward urbanization was soon underway.
The rise of American cities during the 19th century was spurred on by the Industrial Revolution, which created a high demand for labor. Cities became population magnets, drawing workers from around the country and eventually around the world. One generation after another, people left the American countryside behind and headed for the nation’s new and growing cities. The scales began to slowly but inexorably tip in that direction, and today’s census numbers are practically reversed from those of 1790.
For most of American history though, rural populations did not actually diminish. Quite to the contrary, they continued to grow rather robustly. They were simply not able to keep pace with runaway expansion of booming new cities. Thus, rural America’s overall volume rose even as its share of the national population decreased. Two factors explain rural growth despite the urban syphon: natural 
increase and immigration.
Agricultural families typically had a higher birth rate than urban families because children provided valuable labor on the farm from an early age. At the same time, rural America received its fair share of foreign immigrants. While stereotypes of 19th and early 20th century immigration often focus on Irish, Italians, and Jews making new homes in American cities, waves of Germans, Scandinavians, Slavs, British, and many others passed right through those cities and continued on to the heartland.
The draw to rural America was strong, particularly for European farmers who had lost land amid the economic, social, and political tumult in their homelands. Over here meanwhile, the colonial conquest of Native nations and the federal government’s seizure of millions of acres led to successive land booms and rushes. Dating back to the Revolution, the United States had a history of seizing Indian acreage and giving it away on the cheap, the most famous example being the 1863 Homestead Act. Of course, much 
of the land also ended up in the hands of speculators and railroad companies who charged maximum market rates, but even that was often attractive compared to land prices in much of Europe.
Just as cities were finally gaining a majority of the population during the early 20th century, several new factors conspired to severely temper rural growth. The first was immigration restriction. It began with the targeted Chinese Exclusion Act of 1882, evolved over the next few decades into more wide-ranging and comprehensive restrictions, and culminated with the Johnson-Reed Act of 1924. Many “non-white” immigrants were banned altogether, and immigration policy was defined by national quotas. Now only about 350,000 slots for were available per year for immigrants to the U.S. Previously, they had been arriving by the millions.
At the same time the number of foreign immigrants dwindled, fewer Americans found the countryside enticing for a number of reasons. The nation was no longer expanding, and so land prices were not as cheap as they had once been; the mechanization of farming had led to a decreased demand for labor; and tumbling commodity prices and rising debt made farming more tenuous and less appealing.
By the 1920s, the rural population was in a state of decline in some areas for several reasons. The U.S. 
agricultural economy went into depression immediately following World War I, a full decade before the Great Depression. America’s traditional farming economy began to collapse. And in parts of the Great Plains, the Dust Bowl of the 1930s proved to be one of history’s major environmental calamities, further encouraging emigration from rural areas. Some states took decades to recover the population they lost during the Depression. North Dakota still had fewer people in 2010 than it did in 1930.
After the Depression, World War II encouraged yet more people to vacate rural America. Mobilizing for the war led to the building and expansion of thousands of new factories and the creation of millions of new jobs in cities across nation. Rural depopulation plowed ahead with unprecedented vigor. After the war, the trend slowed but continued. My own family, on my father’s side, is a fairly typical example.
My father is descended from people who had lived on farms and in small towns in western North Carolina since the 1700s. Several young men left the state to find work during the Depression. Many of them then left to fight in the war. Upon returning home, the Reinhardts decided to cast their lots elsewhere. My father was still a boy when his nuclear family and a number of extended relatives left farm life behind. They all headed west for the San Joaquin Valley of central California, where many of 
them and their descendants remain. Today, I still have distant relatives in North Carolina, but so far as I know, there are no Reinhardts left in Catawba County.
As Americans deserted the countryside during and after World War II, rural America began to sag. The trend has largely continued unabated down to the present day. Since 1990, over 700 rural counties have lost at least 10% of their population. Half of all rural counties in America now have more deaths per year than births.
In the next article, I’ll discuss how the population decline has re-shaped rural America.