Tennessee State Route 78
| Lake Road | ||||
SR 78; primary in red, secondary in blue | ||||
| Route information | ||||
| Maintained by TDOT | ||||
| Length | 36.93 mi (59.43 km) | |||
| Existed | October 1, 1923–present | |||
| Major junctions | ||||
| South end | SR 104 in Dyersburg | |||
| US 51 in Dyersburg I-155 / US 412 in Dyersburg | ||||
| North end | KY 94 at Kentucky/Tennessee State Line | |||
| Location | ||||
| Country | United States | |||
| State | Tennessee | |||
| Counties | Dyer, Obion, Lake | |||
| Highway system | ||||
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State Route 78 (SR 78) is a 36.93-mile (59.43 km) long primary state highway in northwestern Tennessee, USA. This highway carries a dual primary and secondary designation, however, the majority of this highway is signed as a Primary State Highway. The only portion of SR 78 designated as secondary is between its southern terminus at SR 104 to US 51 in Dyersburg.