| State: | UT |
| Type: | SR |
| Route: | 78 |
| Map Custom: | yes |
| Map Notes: | SR-78 highlighted in red |
| Section: | 113 |
| Length Mi: | 9.418 |
| Length Round: | 3 |
| Length Ref: | [1] |
| Established: | 1977 |
| Direction A: | South |
| Terminus A: | at Mills Junction |
| Direction B: | North |
| Terminus B: | in Levan |
| Previous Type: | SR |
| Previous Route: | 77 |
| Next Type: | SR |
| Next Route: | 79 |
State Route 78 (SR-78) is a 9.418-longNaN-long state highway in the U.S. state of Utah that serves as a connector from the town of Levan and SR-28 to Interstate 15 (I-15) and the Chicken Creek Reservoir. The route was formed in 1977 and has preserved its initial state since then.
The road begins at a diamond interchange with I-15 at exit 207. From that point, the route heads northwest as a two-lane undivided highway, running almost parallel to I-15 in the west and Chicken Creek Reservoir in the east. Once the route passes the reservoir, it eventually turns north-northwesterly until reaching the intersection of a local road, where it turns east. The route enters Levan as 100 North and soon terminates at SR-28, the main street of Levan.[2]
The east–west portion of SR-78 between Levan and Elevator Road is a part of the National Highway System.[3]
In 1975, as Interstate 15 was being constructed in the area, State Route 163 was designated along the old alignment of US-91 from I-15 at Mills Junction to SR-28 in Levan.[4] Since this route shared a number with U.S. Route 163 in southern Utah, it was renumbered to SR-78 in the 1977 Utah state route renumbering. The only change that has occurred to the route since then was a change to the legal definition in 1987, making it more detailed.[5]