Not a named place as most places don't have much out yet, but I have seen shroom compost all over the place in SE Wisconsin. Menards has carried some I believe, maybe even Walmart, I can't recall. I would just call the garden centers and nurseries. Shouldn't take long to find.

It is still a bit early though so a lot of places that will carry it probably don't have it yet.

i heard there was a place somewhere aroud eden that grows mushrooms and sells compost in bulk . but i don't know the address .
jim

Hi-
They definitely have it at Home Depot, but it's in bags. Not sure exactly where you are, but Breezy Hill between Silve Lake and Lake Geneva may carry it in bulk.

If you are looking for compost straight from the grower,

River Valley Mushrooms has bag and bulk -- you load. It's HEAVY
39900 West 60th Street : Burlington, WI : 53105
888-711-7476

I've bought from them. It is expensive but has great texture. Much different from the garden center bagged stuff.

Other possibilities:

I've heard there is a grower near Watertown who can load a farm wagon. From Google, it might be Palm Mushroom Cellars in Helenville.

Also
Gourmet's Delight Mushroom Farm
Eden, WI 53019