| | Parsippany-Troy Hills, NJ | Iselin, NJ | United States |
| Percent Religious | 60.0% | 57.0% | 49.4% |
| Baptist | 0.8% | 1.9% | 8.2% |
| Episcopalian | 1.2% | 0.6% | 0.6% |
| Catholic | 42.8% | 42.0% | 19.7% |
| Church of Jesus Christ | 0.4% | 0.2% | 2.1% |
| Lutheran | 1.2% | 0.6% | 2.4% |
| Pentecostal | 0.4% | 0.3% | 1.9% |
| Methodist | 2.1% | 1.1% | 4.0% |
| Presbyterian | 2.5% | 1.1% | 1.7% |
| Other Christian | 4.3% | 3.3% | 6.7% |
| Judaism | 1.6% | 1.9% | 0.7% |
| Eastern | 1.6% | 1.8% | 0.5% |
| Islam | 0.9% | 2.2% | 0.9% |