Wikipedia
Bilhah (בִּלְהָה "faltering; bashful", Standard Hebrew Bilha, Tiberian Hebrew Bilhâ) is a person mentioned in the Book of Genesis. describes her as Laban's handmaid, who was given to Rachel to be her handmaid on Rachel's marriage to Jacob. When Rachel failed to have children, Rachel gave Bilhah to Jacob "to wife" to bear him children. Bilhah gave birth to two sons, who Rachel claimed as her own and named Dan and Naphtali. (, ) (the use in the Torah of the prefix "to", as in "took to wife", may indicate that the wife is a concubine or inferior wife). expressly calls Bilhah Jacob's concubine, a pilegesh.)
The Testament of Naftali, part of the Dead Sea Scrolls, says that Bilhah and Zilpah's father was named Ahotay. He was taken into captivity but redeemed by Laban, Rachel and Leah's father, who gave Ahotay a wife named Hannah, who was their mother. Rabbinic sources (Midrash Raba, and elsewhere), on the other hand, state that Bilhah and Zilpah were also Laban's daughters, through his concubines, making them half-sisters to Rachel and Leah. (See also, Pirke De-Rabbi Eliezer, xxxvi.)
Bilhah is said to be buried in the Tomb of the Matriarchs in Tiberias.
In the Book of Chronicles, Shimei's brothers were said to have lived in a town called Bilhah and surrounding territories prior to the reign of David.