| State: | OH |
| Type: | SR |
| Route: | 669 |
| Map: | OH 669 map.svg |
| Length Mi: | 32.68 |
| Length Round: | 2 |
| Length Ref: | [1] |
| Established: | 1937 |
| Direction A: | West |
| Terminus A: | near Somerset |
| Direction B: | East |
| Terminus B: | in Malta |
| Counties: | Perry, Morgan |
| Previous Type: | SR |
| Previous Route: | 668 |
| Next Type: | I |
| Next Route: | 670 |
State Route 669 (SR 669) is an east–west state highway in Perry and Morgan Counties in the US state of Ohio. The western terminus of SR 669 is at an intersection with SR 13, southeast of Somerset. The eastern terminus of SR 669 at an intersection with SR 37 and SR 78. Most of the route is a rural two-lane highway and passes through woodland, farmland, and residential properties. For some of its path, SR 669 runs generally parallel to the west of Muskingum River. SR 669 was commissioned in 1937, along a similar route to today. The highway was extended to its current western terminus in 1938. The entire route was paved by the mid-1950s.
SR 669 begins at a T-intersection with SR 13, southeast of Somerset. The highway heads towards the east passing through farmland and woodland, as a two-lane highway. The highway has a T-intersection with SR 345, SR 669 heads northeast concurrent with SR 345. The road passes through residential area, before SR 669 leaves SR 345. SR 669 heads towards the southeast passes through woodland, as a two-lane highway. The route enters Crooksville, passing through residential properties. The highway has an intersection with SR 93, SR 669 turns south concurrent with SR 93. The concurrency head towards south-southeast, as a four-lane divided highway, before becoming a two-lane highway. The highway passes through woodland and crosses over a railroad track.
The concurrency ends at an intersection with SR 669 turning towards the east and SR 93 continuing towards the south. The highway heads east through woodland, with some farmland and houses. SR 669 begins a concurrency with SR 555, heading towards the north-northeast. The concurrency ends with SR 669 heading towards the east and SR 555 continuing towards the north. SR 669 heads east-southeast through woodland as a two-lane highway. The highway makes a sharp turn on the banks of the Muskingum River. The road parallels the river on the west banks of the river, until the road enter Malta. In Malta the highway makes a sharp curve towards the southwest, followed by a curve towards the southeast. The road continues towards the southeast, passing through residential properties in Malta. SR 669 ends at an intersection with SR 37 and SR 78.
SR 669 was commissioned in 1937, on the same route as today between Crooksville and Malta. In 1938 the route was extended west to its current western terminus, replacing SR 663. The first section of route paved was between Crooksville and Deavertown, which was paved in 1942. The final section was paved between 1957 and 1959, this section was between SR 555 and Eagleport.