According to Genesis, which son of Jacob was born first?

According to Genesis, Reuben was the firstborn son of Jacob.

Reuben was the eldest son of Jacob and Leah. Genesis lists him first among Jacob’s sons, who became ancestors of the twelve tribes of Israel. His name is connected in the text with Leah’s hope that Jacob would now love her because the Lord had seen her affliction.

As Jacob’s firstborn, Reuben held a position of seniority, but Genesis later records actions that damaged his standing. He tried to rescue Joseph when the other brothers planned to kill him, proposing that they place Joseph in a pit instead. Reuben was absent when the brothers sold Joseph to traders.

The tribe of Reuben settled east of the Jordan River, alongside Gad and part of Manasseh. Reuben is therefore both the name of Jacob’s son and the name of an Israelite tribe.