Census Bureau: Midwest Home To Most Of The Counties With Decreases In Median Age

Nationally, the population of all race and ethnic groups, except for the non-Hispanic white alone group, grew between July 1, 2016, and July 1, 2017. …

Approximately half (51.4 percent) of the nation’s 531 counties that were getting younger between April 2010 and July 2017 were in the Midwest, according to newly released 2017 population estimates.

Out of the counties that were getting younger, the South also had a high proportion (32.4 percent) of the counties that experienced a decrease in median age — the age where half of the population is younger and the other half is older— followed by the West (14.1 percent), and the Northeast (2.1 percent).

“Nationally, almost 17 percent of counties saw a decrease in median age from April 2010 to July 2017. The majority of the counties getting younger were in the Midwest, and of these counties with 10,000 people or more in July 2017, some of the largest decreases were in North Dakota, South Dakota and Nebraska,” said Molly Cromwell, a demographer at the U.S. Census Bureau. “Williams County, N.D., had the largest decrease in median age, declining by 7.1 years.”

Despite the decrease in median age in many of the Midwest’s counties, a majority of counties in the country continued to grow older. The nation as a whole experienced a median age increase from 37.2 years to 38.0 years during the period 2010 to 2017. This continued aging of the country is consistent with the projected changes to the nation’s population through 2060.

“Baby boomers, and millennials alike, are responsible for this trend in increased aging,” Cromwell said. “Boomers continue to age and are slowly outnumbering children as the birth rate has declined steadily over the last decade.”

Last year, Florida had the largest percentage of seniors (age 65 and older) with 20.1 percent, followed by Maine (19.9 percent) and West Virginia (19.4 percent). Maine also saw its median age increase to 44.7 from 42.7 years old in 2010, making it the state with the highest median age.

On the other hand, Utah had the smallest percentage of its population age 65 and older (10.8 percent), followed by Alaska (11.2 percent) and the District of Columbia (12.1 percent). Utah is also the state with the lowest median age (30.9 years).

View graphics on change in median age from 2010 to 2017 at the county level and the median age in 2017 to see how the nation has changed.

Population Continues to Become More Diverse

At the same time that the U.S. population becomes older, it also is becoming more diverse by race and ethnicity. Nationally, the population of all race and ethnic groups, except for the non-Hispanic white alone group, grew between July 1, 2016, and July 1, 2017. View our graphic on the age and race distribution from 2010 to 2017 to see how the nation has grown more diverse. References below to the race and ethnic compositions of county populations apply only to those counties with a total population of 10,000 or more.

• The Hispanic population increased 2.1 percent to 58.9 million.

• The black or African-American population increased 1.2 percent to 47.4 million.

• The Asian population increased 3.1 percent to 22.2 million.

• The American Indian or Alaska Native population increased 1.3 percent to 6.8 million.

• The Native Hawaiian or Other Pacific Islander population increased 2.1 percent to 1.6 million.

• The population of those Two or More Races increased 2.9 percent to 8.7 million.

• The white alone-or-in-combination population increased 0.5 percent to 257.4 million.

• The non-Hispanic white alone population decreased .02 percent to 197.8 million.

The Hispanic Population (All Races) 

• The Hispanic population made up 18.1 percent of the nation’s total population in 2017, primarily due to natural increase (the difference between births and deaths).

• California had the largest Hispanic population (15.5 million), and Texas saw the largest numeric increase in Hispanic population (234,000 people).

• Los Angeles County, Calif., had the largest Hispanic population of any county (4.9 million), and Starr County, Texas, had the highest percentage of Hispanics with 96.3 percent.

The Black or African-American Population

• Texas had the largest black or African-American population (3.8 million) and the District of Columbia had the highest percentage of the black or African American alone-or-in-combination population (48.8 percent).

• Cook County, Ill., had the largest black or African-American population of any county (1.3 million).

• Clark County, Nev. had the largest numeric increase of black or African-American population of any county (14,000). There were 104 counties nationwide that had a majority black or African-American population, led by Holmes County, Miss. (83.2 percent).

The Asian Population

• Asians were the fastest-growing racial group in the nation. Their increase is primarily due to net migration.

• California had the largest Asian population (6.8 million).

• Hawaii was the only state where the Asian population represented a majority of the population (57.1 percent).

The American Indian or Alaska Native Population

• California had the largest American Indian or Alaska Native population (1.1 million), and Alaska had the highest percentage (20.0 percent).

• Los Angeles County, Calif., had the largest American Indian or Alaska Native population of any county at 233,000.

• Oglala Lakota County, S.D., had the largest percentage of the American Indian or Alaska Native population (93.9 percent).

The Native Hawaiian or Other Pacific Islander Population

• The median age of the Native Hawaiian or Other Pacific Islander population increased the most of any race group (2.3 years), rising from 26.4 years old in April 2010 to 28.7 years old in July 2017.

• Hawaii had the largest number (382,000) and proportion (26.8 percent) of the Native Hawaiian or Other Pacific Islander population.

• Honolulu County, Hawaii, had the largest Native Hawaiian or Other Pacific Islander population (245,000) in 2017. Clark County, Nev., had the largest numeric increase for the Native Hawaiian or Other Pacific Islander population (1,400) in 2017.

The Two or More Races Population

• Those who identify as two or more races made up the second-fastest growing race group (2.9 percent) in the nation. Their growth is due primarily to natural increase.

• The two or more races group had the youngest median age of any other race group at 20.4 years.

• California had the largest two or more races population (1.5 million) and Hawaii had the highest proportion (23.8 percent).

White Alone-or-in-Combination and the Non-Hispanic White Alone Population

• The non-Hispanic white alone group was the only race group to experience population decline between 2016 and 2017 (-0.02 percent). Of all the alone-or-in-combination race groups, the white alone-or-in-combination group grew the slowest (0.5 percent). 

• Both the non-Hispanic white alone and white alone-or-in-combination populations had the highest median ages compared to the other race groups at 43.5 years and 39.2 years, respectively. The non-Hispanic white alone population is projected to continue aging and declining, with one-third of children projected to be non-Hispanic white alone by 2060, as compared to over one-half projected to be older adults.

• The four states with the largest percentage of non-Hispanic white alone populations: Maine (93.3 percent), Vermont (92.9 percent), West Virginia (92.2 percent) and New Hampshire (90.5 percent) are also the four oldest states by median age with 44.7, 42.9, 42.5 and 43.1 years old, respectively.

This is the last of the population estimates for 2017. Previous estimates include national, county, metro area, and city and town population estimates.

The population estimates as of July 1, 2017, do not reflect displacement or other migratory changes to the nation’s population due to Hurricanes Harvey, Irma and Maria in August and September 2017.

For information on how the country is projected to change through 2060, view our previous release, Older People Projected to Outnumber Children for First Time in U.S. History.