An 1844 treaty between the two nations established that United States citizens in China were entitled to extraterritoriality, a form of exemption from the authority of local courts. Under this framework, Americans in China were initially subject to adjudication by consular courts presided over by American officials and governed by American law. In 1906, after complaints about the operations of the consular courts, Congress entrusted their jurisdiction over civil cases involving claims of more than $500 and criminal charges carrying a punishment greater than a $100 fine or six months imprisonment to the newly created United States Court for China (34 Stat. 814). The court exercised appellate jurisdiction over all remaining Chinese consular cases and could also hear appeals from the consular court in Korea “so long as the rights of extraterritoriality shall obtain in favor of the United States.” The law governing the Court’s decisions was a complex blend of federal statutes, English common law, and, in some instances, local Chinese rules. In 1925, the court determined that the United States Constitution did not apply in China.

The court was based in Shanghai and also held sessions in Canton, Tientsin, and Hankau. Its judge was appointed by the President of the United States by and with the advice and consent of the Senate for a ten-year term. The United States Court of Appeals for the Ninth Circuit heard appeals from the court’s judgements. 

During the Second Sino-Japanese and World Wars, Japan invaded and occupied parts of China, including Shanghai. After the United States declared war on Japan following the attack on Pearl Harbor in 1941, Japan ended concessions for Americans in the area and imprisoned the court’s judge. In 1943, the United States signed a treaty with the Chinese government relinquishing any and all extraterritorial rights in China and abolishing the court (57 Stat. 767). 

Further Reading:
Clark, Douglas. Gunboat Justice: British and American Law Courts in China and Japan (1842-1943), Volume 2: Destruction, Disorder and Defiance (1900-1927). Hong Kong: Earnshaw Books, 2015.

Clark, Douglas. Gunboat Justice: British and American Law Courts in China and Japan (1842-1943), Volume 3: Revolution, Resistance and Resurrection (1927-1943). Hong Kong: Earnshaw Books, 2015.

Ruskola, Teemu. "Colonialism without Colonies: On the Extraterritorial Jurisprudence of the U.S. Court for China." Law and Contemporary Problems 71, no. 3 (Summer 2008): 217-242.