Its northern terminus is at an intersection with US 224 approximately 4 miles (6.4 km) east of Ottoville.

[8][9] The road passes through downtown Delphos and mostly residential properties, as a four-lane highway.

The highway turns north onto Fort Jennings Road, ending its concurrency with SR 66.

Fort Jennings Road heads north through residential properties, as a two-lane highway.

[4][5][7][10] SR 190 enters the central part of the village, passing through a mix of residential and commercial properties.

[5][7][10] The SR 190 designation was applied in 1923, on the same route as today north of Fort Jennings.