What kind of wasp lives in holes in the mud/dirt in Illinois? Please see the additional details.?

There are about 100 tiny holes in the same general proximity (15 feet), each hole with one wasp (maybe more), which are black and yellow. I cannot tell if the holes are connected, with a large nest underground, or if they are solitary, although it appears they are solitary. The wasps are currently about 1/2" long. I know they are wasps because of their body shape, but I've not been able to find anything conclusive online about what kind of wasp this may be. It started as about 10-15 holes in the shade of a shrub and the numbers have continued to grow over the past week, with holes all along that side of the house and under the bottom deck railing. They are only in shady areas. We are in Chicago, having just moved from Florida, where I never saw this type of wasp in 33 years (that doesn't mean they aren't there - I just never saw them and I was always gardening!) I am trying to determine a) what kind they are and b) if they are aggressive, as I am allergic to many stinging insects and have two very curious dogs. Any information would be helpful!