They set out from the Desert of Sin and camped at Dophkah.

Exodus 17:1
Then the whole congregation of Israel left the Desert of Sin, moving from place to place as the LORD commanded. They camped at Rephidim, but there was no water for the people to drink.

Numbers 33:11
They set out from the Red Sea and camped in the Desert of Sin.

Numbers 33:13
They set out from Dophkah and camped at Alush.

And they took their journey out of the wilderness of Sin, and encamped in Dophkah.