The highly-contagious strain comprised 41 percent of the state's new variant cases last month, according to state officials.
The Delta variant accounted for 70 percent of New Jersey's variant cases for the week ending June 26, the most recent NJ Department of Health surveillance report shows.
This is the first time that the Delta variant overtook the Alpha variant, first documented in the UK.
Vaccines have proven successful against the variant, which has spread for 80 countries after being detected in India last December.
NJ Health Commissioner Judy Persichilli said that virtually all of the state's COVID-19 deaths and hospitalizations are among those who are unvaccinated.
Click here to follow Daily Voice Washington Township and receive free news updates.