Factually, case law can rest in the decisions of lower courts as well, especially within the jurisdictions of those lower courts, and when the issue in question has not been decided by a higher court.
In the United States, the United States Supreme Court hears cases, decides issues of legal intepretation and establishes precedent through published opinions only on cases related to federal law or the United States Constitution.
In the individual state judicial systems of the United States, the highest court may be styled State Supreme Court, Court of Appeals or other titles. These courts are empowered to render ultimate decisions on issue of state law or their respective state constitution, but lack jurisdiction to interpret issues of civil rights, the United States Constitution, or federal law.
Likewise, under the doctrine of federalism, the United States Supreme Court is powerless to intervene in issues of State Law except to the extent of deciding whether such law complies with the Constitution of the United States or with federal law enacted by Congress.