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According to the latest U.S. Census data released Thursday, 382 people moved into Franklin County as of July 2018 raising the overall population to 103,670. 

Currently, Franklin County ranks 10th among the 114 Missouri counties for total population and is one of only 11 in the state with 100,000 people or more.

In the last eight years, the county population has grown by 2.1 percent gaining 2,178 people from 101,492 at the 2010 census to the 2018 numbers released this week.

The one-year, 0.36 percent increase of 382 residents between 2017 and 2018 is a slight recovery from the previous two years when the county lost 438 residents between 2016 and 2017.

Since 2010 the largest one-year increase in population was between 2015 and 2016 when the county gained 449 new residents.


Currently, there are no counties in Missouri with a population over 1 million people.

Jefferson County also saw a population increase last year, gaining 598 residents. The overall increase since the 2010 census is 2.5 percent or 5,614 new residents.

St. Louis County, with its 996,945 residents in 2018, has the largest population in the state. It has been stagnant since 2010 and has actually lost 0.2 percent, or 2,009 of its residents since 2010.

Between 2012 and 2015 St. Louis County boasted a million-plus population but has experienced a rapid decline beginning in 2015.

The majority of that population loss came between 2015 and 2016, with 3,188 residents exiting the county.

St. Charles County has the third largest population in the state at 399,182 and posted the highest growth in this area.

Between 2017 and 2018 the population increased by 3,937 residents. In the past seven years the population has grown 10.7 percent gaining 38,697 new residents between 2010 and July 2018.

Warren County, which has about one-third of the residents as Franklin County, has also shown a significant increase of 6.7 percent since 2010 (32,513) gaining 2,198 residents to 34,711.

Last year, the population grew by 346 new residents. 

The mass exodus from St. Louis city continued in 2018 with the municipality losing another 5,028 residents last year.

Overall the city population has decreased 5.1 percent since the last census dropping from 319,294 residents in 2010 down to 302,838 as of mid-2018.


The census bureau does not currently have 2018 population estimates for individual cities, but according to 2016 numbers, the city with the second-largest population in Franklin County is growing the fastest.

Union —

Since 2010 the city of Union, which has posted a 9.5 percent population increase, is far and away higher than any of the other Franklin County cities with populations over 5,000 people.

In 2010 the population was 10,204 and as of July 2016 it was 11,277.

Washington —

Washington has the largest population of all the cities in Franklin County. The numbers from 2016 show the population at 14,061. In 2010, the population was 65 people less at 13,996. The growth since the 2010 census is plus 0.5 percent.

Pacific —

Pacific surpassed Sullivan in 2015 and now has the third-largest population in the county.

The city has seen a marked increase in population in recent years, growing 2.5 percent. In 2010, the population was recorded as 7,002 and it increased by 208 people to 7,210 in 2016.

Sullivan —

The city of Sullivan is now fourth in county population, but has shortened the gap behind Pacific.

Despite the slight increase, the overall population growth for Sullivan is now 0.5 percent.

In 2010, the population was 7,090 and it increased by 54 residents to 7,135 in 2015, but fell again in 2016 to 7,126.

Part of Sullivan lies within Crawford County.

St. Clair —

St. Clair rounds out the top five largest cities in the county and its population growth has been stagnant since 2010.

The 2016 population was 4,718 and the 2010 population was 4,719, showing no growth, but the loss of just one resident in six years.

Overall the St. Clair population has increased by only 644 people in the past 25 years.

During the 2000 census, the population was recorded at 4,443 and 4,074 in 1990.


According to the U.S. Census Bureau, 2020 census materials were mailed out between March 12 and 20 and if no response is made, reminder letters may be sent between April 20 and 27.

Depending on how likely an area is to respond online, some residents may receive a letter asking them to go online and complete the census form.

Areas that are less likely to respond online will receive a paper questionnaire along with their invitation.