Traveling with frozen breastmilk

Question

I’m looking for advice on how to travel 8.5 hours away with frozen breastmilk. How can i keep the milk frozen?

Answer

When we had milk in a cooler for an extended period of time in vacation, I think it was like 6ish hours, i kept the milk frozen in blocks inside gallon ziploc bags, made sure this was in the center of the cooler and it was surrounded by big ice packs on all sides, top and bottom, then added all of the other food to the cooler around it. It was still completely frozen when we got there.

Answer

I use a insulated bag I got from Amazon and filled it with ice and worked just fine

Answer

We moved 700+ miles and put the frozen milk from a deep freezer into paper bags and then into our rtic cooler and a styrofoam cooler. Made it without an issue.