EDITOR’S NOTE: This is the first part of a weekly series called “Bracing for Impact,” which will explore Knox County’s future as the potential ‘next frontier’ for population growth in central Ohio. Click here to read the introduction to the series, published Sept. 26.
MOUNT VERNON — In order to understand what made Knox County one of Ohio’s fastest-growing counties over the last decade – and what will likely determine its rate of growth in the coming decades – one must first understand the core elements of population growth.
According to the U.S. Census Bureau, there are three main “components of change” that determine whether a population grows or shrinks over a set period of time. Those components are births, deaths and migration.
The change in the population from births and deaths is often combined and referred to as “natural change.” This is calculated by subtracting deaths from births.
The change in population from migration is often referred to as “net migration,” and it’s calculated by subtracting the number of residents who left a community (emigration) from the number who moved there (immigration). The Census Bureau breaks migration up into two categories: domestic and international.
“Populations grow or shrink depending on if they gain people faster than they lose them,” the Census Bureau states on its website. “Looking at an area’s unique combination of natural change and migration helps us understand why its population is changing, and how quickly the change is occurring.”
So, how did Knox County grow over the last decade?
Knox County grew primarily through natural change, according to Census Bureau estimates published in July, less than a month before the new census was released.
There were 7,523 county residents born from 2010-2020, and 6,335 died. This means Knox County saw a net increase of 1,188 residents through natural change during this time.
Meanwhile, migration represented a smaller portion of the county’s growth. The county saw a net increase of 333 residents through migration from 2010-2020, with roughly two-thirds of that increase coming domestically.
Added together, it would appear Knox County gained 1,521 residents over the last decade. But that number falls short of the Census Bureau’s latest tally, released in August, which had Knox County adding 1,800 residents.
Liz Whelan-Jackson, data manager for the Mid-Ohio Regional Planning Commission, noted the above data is considered merely “an estimate series, and it has not yet been ‘controlled’ to the new 2020 Census numbers,” which could account for the shortfall.
“Still, the components data is a good approximation of population change from various sources,” she continued in an email. “With Knox County’s final number landing a little higher than predicted in the estimates, it’s most likely that they underestimated migration by about 300 people (births and deaths are better documented and more predictable, usually, than migration, so those are less likely to be off).”
How does this compare to the rest of Ohio?
The fact that Knox County saw growth in both categories – and particularly through migration – set it apart over the last decade. And regional experts believe this kind of growth could continue to set it apart in decades to come.
Fifty-three of Ohio’s 88 counties experienced natural growth from 2010-2020, but only 21 saw growth through migration. Among those 21 were many of the state’s fastest-growing counties during that time.
Whelan-Jackson drew a direct line between net migration and growth rates in central Ohio. The counties that gained residents through immigration also grew the fastest, while the counties that didn’t either shrunk or experienced only moderate growth overall.
“Net positive migration is the key driver in those fast-growing places,” Whelan-Jackson said.
She expects this trend to continue in the coming decades, as the country’s birth rate declines and its population skews older. Communities that are able to attract new residents through immigration – and keep current residents from leaving – will likely experience the greatest amount of growth in the decades to come.
“Natural increase (births minus deaths) has been steadily declining,” Whelan-Jackson said. “So our growth is increasingly reliant on attracting people to Central Ohio.”
Next week on “Bracing for Impact”: Having understood the role immigration played in Knox County’s growth over the last decade, we’ll take a deeper look at who moved here during that time and why. Then, we’ll begin to look into the future, examining Knox County’s potential for growth in the coming decades.
