[2][3] It was created to operate a portion of the former Rome, Watertown and Ogdensburg Railroad line from Oswego's West Yard to Suspension Bridge in Niagara Falls.

Declining traffic and poor track conditions led to the end of its operation in July 1984.

For a number of years until 2004, the OMID operated fall foliage excursions between Sodus and Newark in conjunction with the Rochester & Genesee Valley Railroad Museum, which owns the former New York Central "Empire State Express" coach cars used for the trips.

On September 16, 2022, the Livonia, Avon & Lakeville Railroad acquired the controlling stake of Ontario Midland by purchasing 55% of its stock according to paperwork filed with the Surface Transportation Board.

[2][3][6] Operations on the Ontario Midland use VHF radio communications at a frequency of 161.370 MHz.