The Constitution (see Article III) (National Archives)

Judiciary Act of 1789, detailing the Supreme Court and the federal court system, with related summary (Federal Judicial Center)

Judiciary Act of 1891 (Evarts Act), establishing the Courts of Appeals, with related summary (Federal Judicial Center)

Brief History of the Courts of Appeals and histories of each individual circuit (see dropdown arrow on left sidebar) (Federal Judicial Center)

Historical Society of the District of Columbia Circuit

Brief History of the Supreme Court (Federal Judicial Center)

History of the Supreme Court, organized by Chief Justice (Supreme Court Historical Society)

Interviews with Supreme Court Justices and other experts, among other information (C-SPAN's The Supreme Court)

Supreme Court Building Tour (Oyez)

Homes of the Supreme Court (Supreme Court Historical Society)