Includes confirmed and probable cases where available. 14-day change trends use 7-day averages.

At least 20 new coronavirus deaths and 306 new cases were reported in Massachusetts on Sept. 16. Over the past week, there have been an average of 365 cases per day, an increase of 3 percent from the average two weeks earlier.

As of Thursday morning, there have been at least 125,600 cases and 9,245 deaths in Massachusetts since the beginning of the pandemic, according to a New York Times database.

Note: As of Aug. 12, Massachusetts updates the number of cases and deaths by county once a week. The state previously updated these counts each day. This change affects daily county trends.

Hot spots Total cases Deaths Per capita Average daily cases per 100,000 people in the past week Few or no cases Share of population with a reported case No cases reported Double-click to zoom into the map. Use two fingers to pan and zoom. Tap for details. Sources: State and local health agencies and hospitals. Population and demographic data from Census Bureau. About this data For total cases and deaths: The map shows the known locations of coronavirus cases by county. Circles are sized by the number of people there who have tested positive or have a probable case of the virus, which may differ from where they contracted the illness. For per capita: Parts of a county with a population density lower than 10 people per square mile are not shaded. For hot spots: The hot spots map shows the share of population with a new reported case over the last week. Parts of a county with a population density lower than 10 people per square mile are not shaded.

Reported cases and deaths by county This table is sorted by places with the most cases per 100,000 residents in the last seven days. Charts are colored to reveal when outbreaks emerged. Cases Deaths Total

cases Per 100,000 Total

deaths Per 100,000 Cases

in last

7 days Per 100,000 Deaths

in last

7 days Per 100,000 Weekly cases per capita Fewer More Massachusetts 125,699 1,824 9,245 134 2,556 37 99 1.4 March 1 Sept. 16 Nantucket 79 693 1 9 33 289 — — Suffolk 23,371 2,907 1,122 140 540 67 11 1.4 Essex 18,770 2,379 1,261 160 316 40 5 0.6 Plymouth 9,431 1,809 755 145 174 33 8 1.5 Middlesex 26,383 1,637 2,115 131 536 33 26 1.6 Bristol 9,599 1,698 675 119 181 32 7 1.2 Worcester 13,927 1,677 1,077 130 249 30 15 1.8 Norfolk 9,889 1,399 1,038 147 173 24 12 1.7 Hampden 7,902 1,694 768 165 109 23 9 1.9 Barnstable 1,690 793 171 80 27 13 3 1.4 Show all About this data Weekly cases per capita shows the share of population with a new reported case for each week. Weeks without a reported case are shaded gray. The table includes new cases and deaths that were reported in the last seven days.

The New York Times is engaged in a comprehensive effort to track details about every reported case in the United States, collecting information from federal, state and local officials around the clock. The numbers in this article are being updated several times a day based on the latest information our journalists are gathering from around the country.

We’re tracking what has reopened in Massachusetts »

New reported cases by day in Massachusetts 0 1,000 2,000 3,000 cases March April May June July Aug. Sept. Probable data released New cases 7-day average These are days with a data reporting anomaly. Read more here Note: The seven-day average is the average of a day and the previous six days of data.

New reported deaths by day in Massachusetts 0 100 200 deaths March April May June July Aug. Sept. Probable data released New deaths 7-day average These are days with a data reporting anomaly. Read more here Note: Scale for deaths chart is adjusted from cases chart to display trend.

The New York Times has found that official tallies in the United States and in more than a dozen other countries have undercounted deaths during the coronavirus outbreak because of limited testing availability.

About the data

In data for Massachusetts, the Times primarily relies on reports from the state. Massachusetts typically releases new data each day. Weekend counts may be lower because fewer sources report to the state. The state reports cases and deaths based on a person’s permanent or usual residence. The Times has identified the following reporting anomalies or methodology changes in the data: Massachusetts reported the results of a large number of backlogged tests performed by Quest Diagnostics dating back to April 13. Massachusetts started reporting probable cases and deaths. This included the cumulative total of probable cases and deaths going back to March 1, leading to a large one-day increase. Massachusetts removed duplicate reports, causing a decrease in the total number of deaths. Massachusetts did not report new cases or deaths during data system maintenance. Massachusetts revised its methodology for probable cases and deaths, removing 8,050 previously announced cases and 26 deaths. As of Aug. 12, Massachusetts reports only lab-confirmed cases by county. The state previously included probable cases. Massachusetts did not report county-level updates from Aug. 12-17. The tallies on this page include probable and confirmed cases and deaths. Confirmed cases and deaths, which are widely considered to be an undercount of the true toll, are counts of individuals whose coronavirus infections were confirmed by a molecular laboratory test. Probable cases and deaths count individuals who meet criteria for other types of testing, symptoms and exposure, as developed by national and local governments. Governments often revise data or report a single-day large increase in cases or deaths from unspecified days without historical revisions, which can cause an irregular pattern in the daily reported figures. The Times is excluding these anomalies from seven-day averages when possible.

Read more about the methodology and download county-level data for coronavirus cases in the United States from The New York Times on GitHub.