How easy is it to find ground venison

It is illegal to sell wild venison, you will have to hunt it yourself or make friends with a hunter. However, there are many ranches across the US who raise farmed venison that you can purchase. Some butchers might have it, but there are options to purchase online. Check out Force of Nature meats. https://forceofnature.com/collections/all/roamranch

In the US, it's nearly impossible to find and legally purchase venison in any form. It's considered a game animal in most states, and in some places it's actually illegal to sell it. You want to be careful purchasing it as well, because since it is a game meat, the inspection standards for that are almost non-existent and inspection may not have been required or done. Short of hunting it yourself, or making friends with a hunter- you might be out of luck at the moment anyway. Since the pandemic started, small processors have been struggling to stay open- and that's where legal venison is processed. So a lot of places which do sell it legally haven't been able to get their deer, or any other game animals, processed for sale.

Often hard to find in standard grocery stores or butchers. Possible in butchers or farmers' markets featuring organic or grass-fed meats.
If not available locally, yes findable (but/and expensive) online.