Lydia Remington is a pre-made deceased Sim, buried in Riverview. She is Hannah Jones's mother. Like her niece Kirsten Remington, she drowned. It is thought that Lydia adopted Hannah, because the latter has no father on her family tree. Others will argue that she didn't because if Hannah has a child, the child sometimes has blue eyes and black hair, even if neither parent has those traits. Though occasionally it has been seen that the adopted child (i.e. Hannah)'s own biological child would show traits of the adopted parent (i.e. Lydia). So it is feasible that Hannah is adopted.
Unlike the other deceased members of Remington family, Lydia was not buried in the garden at her home or anywhere on the lot, but in Old Town Cemetery. This is most likely because she did not die in the fire that her brother, sister in law, nephew, and niece did.
Her hair is originally black, but it's just to hint that she's on her last days of the adult life stage and her hair is getting grey.