They have a plant in Florida, which is why it is so popular for local distribution. IIRC the plant was built about what, 10 years ago? Before that, you could only get it in the Mid Atlantic region (NY, NJ, PA, DE, MD).
I remember (long before being a brewer) how much I loved Yeng Lager and how I loved it because it was 'dark' compared to the BMC beers.
At this point, it's pretty much swill all around. Maybe some of it is still made in the St Clair brewery, but I thought that was for Premium/Premium LIght at this point. I think the others are still made in Pottsville, but I'm not sure.
I took a brewery tour once and it was a lot of fun. Too bad you can't go back into the cellaring caves anymore. I would have loved to see that operation.