The number of housing units in St Charles County grew from a total of 141,355 units in 2010 to 156,324 units in 2018, for an increase of 10.6%, according to the latest data available from the U.S. Census Bureau. As the table below shows, during this same period, the number of housing units in St Lous County and St Louis City remained the same. The surrounding counties, Franklin, Jefferson and Warren, all saw fairly significant increases.