Which well did Isaac name, saying, "At last the LORD has made room for us"?

Answer: Rehoboth

After quarrels over the wells Esek and Sitnah, Isaac dug a third that no one disputed and named it Rehoboth.

“He moved on from there and dug another well, and they did not quarrel over it. He named it Rehoboth and said, “At last the LORD has made room for us, and we will be fruitful in the land.””— Genesis 26:22 (BSB)