James Pierce Maxwell, 9th Baron Farnham (1813 – 26 October 1896) was an Irish peer, Nova Scotia baronet and Member of Parliament.
He was the son of Henry Maxwell, 6th Baron Farnham and Lady Anne Butler. He became a Member of Parliament for County Cavan on 17 February 1843. As Lieutenant Colonel of the 97th Foot he was severely wounded during the Crimean War.
On his brother's death, he succeeded on 4 June 1884 as 9th Baron Farnham, and later the next year, on 4 December 1885, he succeeded his distant cousin as 12th Baronet of Calderwood. He died unmarried and was succeeded by his nephew, Somerset Henry Maxwell.