O'brien Marriage Records: Groom Firstnames
- Jack (3)
- Jame (1)
- James (160)
- James Daniel (1)
- James Gerard (1)
- James H (1)
- James J (1)
- James Joseph (5)
- James Kenneth (1)
- James M (1)
- James P (3)
- James Patrick (1)
- James Peter (1)
- James S (1)
- James Thomas (1)
- James William (1)
- Jason (2)
- Jeff (2)
- Jeffrey (8)
- Jeremiah (7)
- Jeremiah F (1)
- Jeremiah J (1)
- Jeremiah Joseph (1)
- Jerome (4)
- Jerome John (1)
- Jhn (1)
- John (233)
- John A (1)
- John C (1)
- John F (2)
- John Francis (2)
- John J (4)
- John Joseph (1)
- John M (2)
- John P (2)
- John Patrick (4)
- John Ronald (1)
- John W (1)
- Joseph (90)
- Joseph Charles (1)
- Joseph Gerard (1)
- Joshua (2)
- Justin (1)