It was founded on October 5 1979. Ontario Midland was created to save the entire Rome, Watertown and Ogdensburg Railroad (Hojack) line from Oswego's West Yard to Niagara Falls, New York's Suspension Bridge, but the railroad only managed to buy from Hannibal in Oswego County, New York to Webster in Monroe County, New York. The railroad also operates a line formerly operated by Conrail, Penn Central, Pennsylvania Railroad from Wallington, where it meets the Hojack, to Newark to interchange with CSX's ex-Conrail (New York Central) Waterlevel Route.
Operations on the Ontario Midland are carried on VHF radio at a frequency of 161.370MHz. The OMID carries food products, lumber, fertilizer, pulpboard and chemicals. The OMID carries about 850 cars a year and operates 56 miles of track. It operates Monday to Friday from 8:00 a.m. to 4:00 p.m. (8:00-16:00). For a number of years until about 2003, the OMID ran Fall Foliage excursions in conjunction with the Rochester NRHS chapter whom owns the Empire State coach cars that were used for the trips.
The railroad's all time locomotive roster includes, with the exception of #5, an all-Alco roster: