John Charles Bigham, 1st Viscount Mersey (3 August 1840 – 3 September 1929) was a British jurist and politician. After early success as a lawyer, and a less successful spell as a politician, he was appointed a judge, working in commercial law. After his retirement, Mersey remained active in public affairs, and is probably best remembered for heading the official Board of Trade inquiries into the sinking of steamships, most notably the RMS Titanic, the RMS Lusitania, and the RMS Empress of Ireland.