What is expected in the future? Will the suburban counties continue to grow until Indianapolis is swallowed up by the suburbs? Hardly. The chart shows how the region’s population may change over the next four decades, and Indianapolis stays well above the others as far as the eye can see.

The population balance between Indianapolis and the suburban counties collectively already has tipped toward the suburbs. But even far into the future, Indianapolis will dominate the region. Indianapolis’ population is expected to grow from 860,454 in 2000 to nearly a million in 2040. Other Central Indiana counties will grow, and a few will grow at a faster rate than Indianapolis. But none will come close to Indianapolis in size.

If the forecast holds true, Indianapolis will still be about 45.4 percent of the region’s population in 2040. Hamilton County, after several more decades of phenomenal growth, then will account for about 20.1 percent of the region, and will remain less than half the size of Indianapolis. Hendricks, Johnson and Boone counties are expected to grow substantially in coming years, while Morgan, Hancock and Shelby counties will grow slowly and Madison County will decline.

These predictions assume current trends will continue. Any changes in those trends would alter the future envisioned here. What sort of changes might occur? The mind conjures up disaster-movie scenarios of a virulent epidemic or a natural disaster on the scale of Hurricane Katrina. On the plus side, an Indianapolis company could launch the “next big thing” and spark an economic boom that would attract thousands of workers from out of state. But the most probable cause of change in the population growth trend is the natural increase resulting from births in the resident population.