The Great Chieftain o’ the Puddin’ Race.
Haggis is traditionally made from the leftover bits after butchering the lamb, sheep or cow for the good cuts of meat. The leftovers, including the offal are chopped up and mixed with oatmeal, stuffed into the animal’s stomach or intestine to make a big sausage and then boiled.
Modern haggis tends to be made from better stuff, as some of the original ingredients are no longer allowed to be used, at least in the USA. Import of most Scottish haggis to the states is not permitted, so haggis in the US is usually locally manufactured.
I have found the following brands available.
Stahly are a Fife company who invented a way to put haggis in its skin in a tin. Stahly’s haggis in the US is made in Chicago to the same recipe but without the skin-in-the-tin.
McKean’s appear to be selling their haggis (in the skin – frozen) directly from Glasgow to the US. I am not sure how, as MacSween’s clearly still cannot.
Caledonian Kitchen are making lamb and beef haggis in tins in Texas.
Scottish Gourmet USA in New Jersey is a Scottish ex-pat gourmet chef – skinned frozen haggis.