Where is the oil filter located on a 1991 Buick Regal Custom 3800?

On a 1991 Buick Regal Custom with the 3800 V6 engine, the oil filter is typically located on the passenger side (right side) of the engine, towards the front. It's usually fairly accessible, but you might need to maneuver around some other components to reach it. A shop manual or a picture of the engine bay for that specific year and model would give the most precise location.