The total number of active COVID-19 cases in Montgomery County grew by just over a quarter Sept. 1-30, and more than 2,300 total new cases and 26 deaths related to the disease were reported over the course of the month, according to data from the Montgomery County Public Health District. The county's active case count as of Sept. 1 sat at 1,190, including 28 county residents who were hospitalized. By Sept. 30 that figure had risen 26.72% to 1,508, including 18 resident hospitalizations, although active cases peaked in the county at 1,669 on Sept. 21. Active cases in the county peaked earlier this year at 2,597 on July 27, which was just under 45% of total cases confirmed as of that time. The county ended September with 13.6% of all cumulative cases still active. More than 21% of the county's total COVID-19 cases were reported by the health district in September, as the county's cumulative case count rose from the 8,736 confirmed as of Aug. 31 to 11,092 Sept. 30.

However, many of the cases added by the health district in September had first tested positive for COVID-19 in a previous month when they were reported by health care providers to the Texas Department of State Health Services before being processed by the county in September. Based on daily case reports, 859 of the 2,356 new cases added in September—more than 36%—had first been identified earlier this year. As of Oct. 1, the health district was continuing to process some backlogged cases daily. A total of 1,462 county resident recoveries from COVID-19 were also reported in September. As of Sept. 30, a total of 7,455 COVID-19 recoveries had been confirmed in the county, representing more than 67% of all cumulative cases. The total number of resident deaths related to COVID-19 in Montgomery County reached 140 on Sept. 30, including 26 deaths recorded over the course of the month. That figure is lower than the number of fatalities recorded in both July and August.

Below are daily figures for active and recovered cases as well as daily new cases and deaths reported in Montgomery County through September.