The same field which Abraham got from the children of Heth: there Abraham was put to rest with Sarah, his wife.
Referenced Verses
Gen 23:16 : 16 And Abraham took note of the price fixed by Ephron in the hearing of the children of Heth, and gave him four hundred shekels in current money.
Gen 49:31 : 31 There Abraham and Sarah his wife were put to rest, and there they put Isaac and Rebekah his wife, and there I put Leah to rest.