Cedar Point amusement park in Ohio used to have an IMAX theater - I'd seen several traditional IMAX films there growing up The screen was huge and you felt immersed in the experience. It was demolished circa 2015.
Unfortunately, things seemed to have changed. At the Crocker Park Regal theater in Westlake, Ohio, I'd seen The Force Awakens (Star Wars) in 3D IMAX... the screen is what passes for "large" today, but was more of a standard size by size by late 1990s standards (which is small compared to 70s and 80s regular screens).