Allen County, watch your back.
With an estimated 372,877 residents, the county remains Indiana's third largest behind Marion with 950,000 and Lake with 485,640, according to census population estimates released today. But Hamilton County, ranked fourth and the fastest growing in the last decade, is quickly closing in with 323,747 people.
While Allen County had the fourth largest numerical growth between 2016 and 2017 – an estimated 2,900 people – Hamilton grew by 7,451. Hamilton, north of Indianapolis, has averaged 2.5 percent growth each of the last seven years, while Allen averaged less than 1 percent annually. That has narrowed Allen's population lead over Hamilton of nearly 81,000 people in 2010 to 49,000.
In little more than a decade Allen will lose the chase, according to population projections reported this month by the Indiana Business Research Center.
"Our projections show that Hamilton County is expected to race past both Allen and Lake counties over the next few decades and become the state’s second-largest county," Matt Kinghorn, senior demographer for the IBRC and the report's author, said in an email response. "Hamilton is expected to pass Allen County around 2030."
The counties surrounding Indianapolis, including Hamilton, again had the largest single-year growth in the state. Boone County led that region with a 2.55 percent growth rate between 2016 and 2017, according to today's census estimates. Boone, northwest of Indianapolis, has an estimated 65,875 people.
The Indianapolis metro area will continue to be the state’s primary source of growth over the coming decades, according to IBRC's projections. The 11-county region is expected to grow from 1.99 million residents in 2015 to 2.51 million in 2050 – a 26 percent increase, the report states.
Indiana’s population will increase by about 660,000 residents between 2015 and 2050, from an estimated 6.61 million residents to 7.27 million, according to the projections.
But "the state will likely see wide differences between a relatively small number of mostly metro-area communities that will fuel this growth and a large number of mid-sized and rural communities that are projected to see population declines," the report states.
Between 2000 and 2010, 63 of Indiana's 92 counties saw population increases. The number fell to 35 between 2010 and 2015. Yet, an Indiana Business Research Center analysis of the newest census estimates found that 55 counties had a population increase last year – the largest number of Indiana counties to post a gain since 2008. "Even among the communities that continue to lose population, many saw less of a decline in 2017 than they had in recent years," according to an IBRC news release.
Indiana added 32,800 residents in 2017 – a 0.5 percent increase. That is the state's largest annual population gain since 2009 and above the average annual increase of nearly 24,000 residents per year from 2010 to 2016, the IBRC notes. But Indiana's growth in recent years remains below the average gain of 40,300 residents a year it experienced from 2000 to 2010, the release states.
"Indiana's improved population growth was driven by a significant uptick in migration to the state," Kinghorn said in the release. "After averaging a net in-migration of just 940 residents per year over the previous six years, Indiana had a net inflow of more than 10,400 residents in 2017." However, the state's birth rate, which began to decline after the Great Recession, remains low, he added.
The IBRC's projections show only 33 counties will have population increases between 2015 and 2050.
In the past, most counties have had net out-migration, meaning more people moved away than moved in. But many made up for it through a natural increase, or more births than deaths. As the population ages, fewer counties will have enough natural increase to make up the difference, according to the IBRC projections.
Hamilton County will climb to an estimated 528,000 residents in 2050, according to the projections. Marion County will reach a population of nearly 1.07 million people, and Allen County will grow 18 percent to 434,000 residents. Lake County's population is projected to decline by 3 percent.
Elsewhere in northeast Indiana, only Huntington County continued to lose population. Among the other counties, growth was less than 1 percent between 2016 and 2017.
Across the nation, Maricopa County, Arizona, saw a population increase of nearly 74,000, the most of any county last year, according to the data release.
From July 1, 2016, to July 1, 2017, six of the top 10 largest-gaining counties were in Texas: Bexar, Collin, Dallas, Denton, Harris and Tarrant. The remaining four were Maricopa County, Arizona; Clark County, Nevada; Riverside County, California; and King County, Washington.
Most of the nation’s 3,142 counties grew, with 57 percent gaining in the last year.