I use The Langton by Daler Rowney as it's what my local art supplies place has. They do a whole range under the Langton name though so if you go for this, make sure it says "hot pressed". It's nice quality, acid-free, heavy paper - I just found the details here
as I wasn't sure what the weight would be in US terminology. It's 140lb, apparently. Scroll down the page to find the hot press and you can see what sizes are on offer, too.
Somebody on your side of the Atlantic might have a different steer for you in terms of what is readily available if Daler Rowney is not (although from the store locator on the web site it looks as if it's pretty widely carried in the US).