Well, maybe not the dirtiest, but certainly close
Our laundry room also serves as the way out of the house. 95% of the time - we go in and out through the laundry room into the garage. We have baskets for the shoes so we aren't walking around with shoes on the carpets.
Its a good thing!
I can't imagine trying to vacuum out the amount of dirt I just swept out of the laundry room. I pulled the baskets out from their cubbies in the bench that hold shoes to sweep under them as well - Michael's actually had piles of SAND under the basket.
I almost completely filled the dustpan with dirt, dust, and sand from sweeping the laundry room - a room that we spend the least amount of time in, but experiences the most traffic.
And now its clean!