| | Underwood-Petersville, AL | Russellville, AL | United States |
| Percent Religious | 58.9% | 65.1% | 49.4% |
| Baptist | 23.2% | 39.3% | 8.2% |
| Episcopalian | 0.8% | 0.0% | 0.6% |
| Catholic | 2.1% | 4.7% | 19.7% |
| Church of Jesus Christ | 0.7% | 1.5% | 2.1% |
| Lutheran | 0.3% | 0.0% | 2.4% |
| Pentecostal | 0.9% | 3.7% | 1.9% |
| Methodist | 8.6% | 5.2% | 4.0% |
| Presbyterian | 1.5% | 0.1% | 1.7% |
| Other Christian | 20.7% | 10.5% | 6.7% |
| Judaism | 0.0% | 0.0% | 0.7% |
| Eastern | 0.0% | 0.0% | 0.5% |
| Islam | 0.0% | 0.0% | 0.9% |