Exodus 15:23
And when they came to Marah, they could not drink of the waters of Marah, for they were bitter: therefore the name of it was called Marah.
Nave's Topical Index—AKJV

Numbers 33:8
And they departed from before Pihahiroth, and passed through the middle of the sea into the wilderness, and went three days' journey in the wilderness of Etham, and pitched in Marah.
Nave's Topical Index—AKJV