**Updates will be posted once per week (Monday) at 9 a.m.**


    Today we release new data about how COVID-19 has impacted municipalities in New Jersey. WRI has been tracking publicly available data sources (such as individual county health departments) since April of 2020. Scroll below this box for links to a research brief that describes how the first two waves of the pandemic spread across municipalities in New Jersey, as well as a technical description of the process we used to collect, clean, and analyze the data. Using the button below you can access the data after agreeing to the terms.

    On Monday, April 5th, new cases stayed about the same at both the national and state level. The rolling 7-day average for the nation is at 19 new cases per 100K population, and it is 50 new cases per 100K in New Jersey. The country is now at about 25% of its maximum case rate, and the state is at 71% of its maximum rate. Overall, New Jersey's case rate is about 2.5 times higher than the national case rate. In the color-coding of green to red offered by Harvard's Global Health Institute, all but one of New Jersey's counties are in the red zone. New case rates in New Jersey range from 20/100K population in Cumberland County to 74/100K in Sussex County, with Hunterdon, Union, Monmouth, Bergen, Ocean, Hudson, Essex and Passaic counties in the 50's. Case rates are highest in the northeast counties near New York City, second highest in the northwest counties of New Jersey, and lowest in the southern counties in New Jersey.

  1. Cases stayed about the same last week. The total number of new cases in New Jersey between Monday, March 29th and Sunday, April 4th was 30,610, while there were 30,864 cases between Monday, March22nd and Sunday, March 28th. This is a 1% decrease. Cases in the country also stayed about the same, at 443,000 new cases.

  2. In New Jersey, deaths increased last week. New Jersey reported 248 deaths between Monday, March 29th and Sunday, April 4th. New Jersey reported and 215 deaths between Monday, March22nd and Sunday, March 28th. In contrast to New Jersey, deaths decreased nationally, from 6,794 deaths to 5,547 deaths. Because the numbers overall are small for deaths in New Jersey, they are particularly susceptible to noise. [Note: on days where a county reported negative new deaths, we excluded that data point from analysis.]

**All data are downloaded from the Johns Hopkins Coronavirus Github. Data like these are inherently noisy. In the plots, we smooth the data over a 7-day period to help account for the noise. We do not smooth when we report weekly totals. In late June, the state began to include probable deaths as well as confirmed deaths in the numbers reported to the Johns Hopkins database. This caused a large spike in the reported number of new deaths. We included these in the total deaths, but took the spike out of the incremental day analysis to avoid a misleading spike in the graph. Each date's data point includes the average of data seven days prior to that date Please consider these daily plots as a useful rough sketch. State reports and detailed models provide additional information. There are often reports of "negative" deaths and cases, which likely occurs as data are updated. For use in percent changes, we remove "negative values" from the calculations involving increments, but we leave them in the calculations that report cumulative values. For counties with reports of "negative" new cases, we report the data as missing in the heat map.

Contact Sarah Allred at srallred@camden.rutgers.edu

Municipal-level Data

In New Jersey, it has been difficult to obtain official data about the number of positive COVID-19 tests in each municipality. However, many county health departments and other public sources report the number of confirmed COVID-19 cases in municipalities each day. On April 22, 2020, WRI began tracking these sources. A research brief describing and analyzing two waves of COVID-19 cases in New Jersey utilizing this data is here. The methods used to collect and analyze the data are described in a technical document here.

This dataset is the number of confirmed COVID-19 cases in municipalities throughout New Jersey on April 27, 2020; June 30, 2020; and December 13, 2020.

Regional Definitions (based on disease progression)

  • Northeast: Bergen, Essex, Hudson, Middlesex, Monmouth, Ocean, Passaic and Union counties (counties with >1000 cases on April 1).
  • Northwest: Hunterdon, Mercer, Morris, Somerset, Sussex and Warren counties.
  • South: Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Salem Counties.

Where we are now: New Cases Each Day Per 100,000 Population


  • Recently, cases are decreasing across the state. New Jersey has released guidelines mandating that travelers from certain states quarantine for two weeks when entering New Jersey. The dashed line represents the threshold in cases for a state to be placed on the quarantine list.

Where we are now: New Deaths Each Day Per 100,000 Population


  • The plots over time show deaths decreasing. Harvard's Global Health Institute recommends that deaths, as well as cases, be used to determine the severity of the pandemic. The dashed line here represents the level of deaths that is equivalent (in terms of disease spread) to the out-of-state quarantine line in the "cases" plot. Because the numbers overall are small for deaths in New Jersey, they are particularly susceptible to noise.

County-Level Plots: new cases each day per 100,000 population

County-Level Plots: new deaths each day per 100,000 population

Technical Notes:
  1. Data are downloaded from JHU Github approximately 7 a.m. each day. JHU Github sometimes lags New Jersey Department of Health Dashboard.
  2. Day 10 (March 31, 2020) of the JHU Github appeared to contain incorrect data for deaths. We averaged days 9 and 11 to get day 10. Day 31 also contained incorrect data, so we performed a similar averaging procedure. On day 36, Hudson County reported a lower number of total deaths than on day 35. To avoid “negative deaths”, we adjusted the death estimates for the previous days.
  3. Population estimates are from the 2010 Census.


The plots here visualize the progress of COVID-19 across three regions in New Jersey. New cases (first figure) and new deaths (second figure) are shown on the y-axis, and time (in days) is shown on the x-axis. To account for population differences between the three regions, we plot the number of new cases (or deaths) per 100,000 population. For example, if the value on the y-axis is 10, that would mean that 10 out of every 100,000 people tested positive for COVID-19 the previous day. The first day on the graph is March 22, 2020.

We plot a rolling 7-day average of the data. This means that each days number is an average of 7 days. We do this because there are variations in the time it takes to report deaths. For example, a health department might be overwhelmed and unable to enter all the deaths on one day, making the numbers look lower than they should.

In addition to plotting data by county, we also average across three regions of the state. The first is northeastern counties. These are counties that had more than 1000 infections each on 4/1/2020, and include Bergen, Essex, Hudson, Middlesex, Monmouth, Ocean, Passaic and Union counties. The second is northwestern counties. These all had fewer than 1000 infections on 4/1/2020. The third is southern counties, including Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, and Salem counties. These counties had fewer than 250 cases on 4/1/2020.