| Province: | NB |
| Type: | NB |
| Route: | 104 |
| Length Km: | 82.76 |
| Maint: | New Brunswick Department of Transportation |
| Length Ref: | [1] |
| Length Round: | 1 |
| Established: | 1965 |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | in Lower Brighton |
| Cities: | Coldstream, Nackawic-Millville, Burtts Corner Zealand |
| Terminus B: | in Mouth of Keswick |
| Previous Type: | NB |
| Previous Route: | 103 |
| Next Type: | NB |
| Next Route: | 105 |
Route 104 is a highway in New Brunswick, Canada, running from an intersection with the Trans-Canada Highway near Hartland to an intersection with Route 105 at Mouth of Keswick (near Fredericton), a distance of 83 kilometres.
From Hartland, Route 104 follows the Becaguimec Stream to the north traveling east through the communities of Coldstream at the south terminus of Route 570, Lower Windsor at the south terminus of Route 580 before turning south east. The road travels through Carlisle and Cloverdale, the east terminus of Route 575, turning southeast through uninhabited forest land through the villages of Maplewood, Hawkins Corner at Route 585, Nackawic-Millville past the north-east terminus of Route 605. The road continues east through Hainesville past the north-east terminus of Route 610, Greenhill, and past the Crabbe Mountain ski hill, Brewers Mills, Morehouse Corner, past the north terminus of Route 616 to the rural community of Zealand. Route 104 then follows the Keswick River, crossing it at Burtts Corner at the south terminus of Route 617, turning south to follow the river's east bank to its end at Mouth of Keswick though Pughs Crossing, ending at Keswick.