Editor's note: This story has been updated to include 2018 5-year population estimates from the U.S. Census Bureau for each ZIP code.

ZIP code 77377 has the highest number of coronavirus cases in Tomball and Magnolia with 48 confirmed cases as of May 4.

Updated Harris County Public Health Department and Montgomery County data shows an increase in the number of coronavirus cases since April 14.

ZIP code 77375 has had the largest increase from April 14 data, from 11-20 cases to 47 confirmed cases.

ZIP code 77377 was home to 37,016 residents in 2018, according to the 2018 U.S. Census Bureau's American Community Survey five-year estimates, which follows ZIP code 77375 with 52,785 residents for highest population in the Tomball and Magnolia area.


The remaining local ZIP codes followed with: ZIP code 77354 home to 30,215, ZIP code 77355 home to 24,110 residents, ZIP code 77447 home to 11,872 residents and ZIP code 77362 home to 4,600.

In total, there were 148 confirmed cases of the coronavirus in the six ZIP codes as of May 4, which is 0.09% of the area population.

Here are the case number ranges for Tomball- and Magnolia-area ZIP codes, per the latest available data May 4:
  • ZIP 77447: 9* (This ZIP code includes Harris and Montgomery County. One case, which has since recovered, was listed in Montgomery County; the eight remaining cases are listed in Harris County)
  • ZIP 77354: 29 (This includes 22 active cases and seven recoveries)
  • ZIP 77355: 13 (This includes 12 active cases with one recovery)
  • ZIP 77362: 2 (This includes two active cases)
  • ZIP 77375: 47*
  • ZIP 77377: 48*
As of 4:30 p.m. May 4, there were 6,967 cases in Harris County with 2,504 recoveries and 640 cases in Montgomery County with 163 recoveries.

*These ZIP codes are not broken down into active cases and recoveries because the Harris County Public Health Department does not break down ZIP code data by case status.