Compared to the other cities in New Jersey and cities in all other U.S. states, how safe is Leonia, NJ? From the gauges displayed above, you will notice that Leonia, NJ has been ranked safer than 82% of other cities in the state of New Jersey. In addition, Leonia, NJ is safer than 92% of cities in the entire United States. To achieve these results, all New Jersey and United States cities were analyzed to determine how many locations had a lower crime rate than Leonia, NJ. By studying this data, it was possible to determine that Leonia, NJ is above average in safety when compared with other United States cities.