Five-year estimates collected through the U.S. Census Bureau's 2015-19 American Community Survey, released Dec. 10, show growth across several demographic categories in Montgomery County this decade.

Montgomery County had previously been identified as one of the fastest-growing in the state based on one-year Census estimates. According to the new estimates covering the past five years of data, the county grew to an estimated population of 571,949 over the latter half of the decade, an increase of more than 17% from the estimated 487,028 residents reported in the 2014 ACS five-year estimate covering 2010-14. The county also grew older between the two five-year periods, with the median age of 36.3 recorded in the 2014 survey increasing around 2.2% to 37.1 in the 2019 survey. The share of Montgomery County residents ages 0-59 also fell slightly between 2010-14 and 2015-19, while the share of residents ages 60 and over increased by more than 10%. Alongside population and age, the county's educational attainment and median household income also increased through the 2010s. The percentage of county residents who achieved a high school diploma or higher among those age 25 and above rose slightly from the 86.4% share reported in 2014 to 87.7% in 2019. The proportion of county residents older than 25 with a bachelor's degree or higher also increased by several percentage points, from 31.7% in 2014 to 34.5% in 2019. The median household income of $68,840 recorded in Montgomery County through the 2014 community survey rose 17.52%, to the median income of $80,902 recorded in the 2019 survey.

The county's employed population among those age 16 and older grew by more than 21% over that time, from 224,133 to 272,189; this also represents a 3.41% increase in the share of the county's population that was employed. The county's racial demographics remained relatively similar between 2010-14 and 2015-19. More than 86% of county residents identified as white throughout the decade—although that share decreased by around 0.5% between the five-year spans—while the share of Black or African American and Asian county residents rose by 0.6% and 0.4%, respectively, over that time. The Hispanic or Latino population grew from 21.7% of the county's population to 24.1% between the five-year spans.