1983 was the first year for Ross to offer a true mountain bike. (The 1982 catalog lists only the Diamond Cruiser which was pretty much just a beach cruiser with 10 speeds and a once piece crank.
I remember all the models were named after Pac NW mountains, Mt. Hood, Mt. Washington, Mt. Rainier, Mt. St Helens, and Mt. Whitney were the models.
The bikes were built in Allentown, PA.
This was likely the peak era for Ross bikes as they were also offering the Signature series line of road bikes around that same time, but sadly but the end of the decade, they'd be gone, succumbed to the all the cheap import brands and for a while reduced to a cheap department store line of bikes under the Rand label.
Ross made some decent bikes back then, from 1983 through about 1987 they were selling a ton of bikes, most all with good reviews.