Exodus 9:4, 6, 26

But the LORD will make a distinction between the livestock of Israel and that of Egypt, so that no animal belonging to the Israelites will die.’ ”

And the next day the LORD did it: All the livestock of the Egyptians died, but not one animal belonging to the Israelites died.

The only place it did not hail was the land of Goshen, where the Israelites were.