Arent steelhead just rainbow trout or are they a different species?
Depends who you ask.
Also where the line is drawn differs, again depending on who you ask.
Generally, in the company of non-anglers, or those who aren't as "into it" as me within the state of PA, I'll call the big salmonids in Erie "steelhead" and leave it at that. When talking with friends from the PNW, many of whom look down on the existence of the great lakes salmonids and refuse to consider them steelhead, I'll qualify them by calling them "Great Lakes steelhead", "lake run rainbows", or "Erie steel". I'll also jokingly call them "steelbows", "mutts", or "rustheads", the last given their proximity to the Rust Belt cities. Whether due to genetic differences or by virtue of their being, at adult size, an apex predator in the lakes and having little current to fight or thousands of miles to cross, they do indeed get fat...
Again, if you're dead set on the state of Ohio
you should seek the help of a mental health professional, there's not much practical fishing advice I'd feel qualified to give you, since the PA steelhead game is so different due to the way you approach fishing for a 10 lb trout in a stream that is often less than 20 feet across. If you're thinking of straying into the PA water during your eventual trip, that's where I can help out. But if you decide to do that, come here first...or wash your gear thoroughly at the border.