Minimum connection time at O'Hare traveling from Kansas City to Dublin

Is it a single booking? If so, probably OK. Its the airline's responsibility to get you to your destination. Thus its in their interest to schedule flights so connections can be made.

If 2 separate bookings, that is too short for my comfort zone. If your KC to CHI flight is late and you miss your CHI to Dublin flight, you are stuck for the cost of a new ticket.( Or at least having to pay a re-booking fee and fare difference). And when the next flight with seats will be is another issue.

You should be fine since you arrive and depart from terminal 1, however, I always prefer a layover of 2-3 hours in case the first leg takes off a bit late.

In the past I have tried to have at least two hours for international flights but have now moved to three - for both there and back. That doesn't mean I will get it if there are changes, but this is what I am trying for. This past winter we were a little late taking off from Jax and then when we got to ATL "the inn was full" - no place to land, so we spent some time circling until it was our turn. We were in first class so were off quickly. Hubby did still have time to have one last smoke before boarding the long haul but we had to hurry for him to be able to do it. Remember - your flight will start boarding 45 minutes to an hour before takeoff.

I would go longer three plus hours. I fly in & out of O'Hare often and while if it is one ticket they have to get you there I personally wouldn't want the stress for my vacation. You could have t storms in Sept or other delays.

Our usual domestic to international connection is 1.5 hours but did a one hour transfer time last fall through ORD. No problems.

Having done that route, I'd opt for more time. If its a regional jet, (most United from KC seem to be), your carryon might be gate checked. Plus it can take more than a few minutes to deplane, and likely at another concourse than the international flight. Since boarding the international flight on a wide body may start an hour before flight, they might be boarding by the time you get to the gate.

Thank you all for your suggestions. We've opted for a longer layover just to be on the safe side.

I use to work at Ohare international flights
You will make it as long as the flight from KC is not grossly delayed.
If so they will put you on one of the other two direct flights following yours after 5:30 on
Aer Lingus or American; so you are basically getting the longer layover