W-2 with JR Simplot name (comes from corporate which is in Boise)
wikipedia which shows Simplot makes McDonald's fries (third paragraph under J.R. Simplot Company)
google street view of the factory outside (easier than driving)
Update: I realized that I needed to add some context here because all of this information is useless if it leads you to false conclusions and assumptions. Take the anecdotes with a few grains of salt. There are upwards of 2 millions of pounds of fries (not just McDonald's fries) processed at the factory every day. The chance that you will be the lucky person to chance upon a disgusting box of fries that should not have made it out the door is nearly negligible, which to be quite frank is why that happens in the first place. Also, realize that this is true for most food processing facilities. It becomes cost prohibitive to weed out all the stupids and ensure everything is engineered in a way to eliminate all negative happenings. This is a reality of the world we live in today. Do not assume that all the awful things I have mentioned here will happen to you - but remember that so long as you eat processed food, they will likely happen to you at least a few times in your life (by the way, I am not judging people for eating processed food because I eat it too)!
edit: Finishing up with all the unanswered questions. I'll be deleting this account after this just in case company lawyers somehow get involved. I hope everybody enjoyed this!