James Grenville, 1st Baron Glastonbury

James Grenville, 1st Baron Glastonbury, PC (6 July 1742 – 26 April 1825), was a British politician associated with Butleigh Court in Somerset. His career included membership in both houses of Parliament.

He was the eldest son of James Grenville (12 February 1715 – 14 September 1783), who also served as a Member of Parliament. James Grenville was related to George Nugent-Temple-Grenville, 1st Marquess of Buckingham, as a first cousin. The Grenville family was influential in southeastern England, particularly in Buckinghamshire, during the 18th and early 19th centuries. They maintained a significant political presence, often representing parliamentary boroughs such as Buckinghamshire and Buckingham, and produced notable political figures, including two Prime Ministers, George Grenville and William Wyndham Grenville, 1st Baron Grenville. The family had connections to William Pitt the Elder and William Pitt the Younger.

James Grenville received education at Eton College and Christ Church, Oxford. His early parliamentary service began as a Member of Parliament for Thirsk, a borough in Yorkshire, from 1766 to 1768. Subsequently, he represented the family borough of Buckingham from 1770 to 1790, serving alongside his twin brother Richard from 1774 to 1780. Following the death of his father in 1783, he succeeded to the family estates.

In the period from 1790 to 1797, Grenville was the Member of Parliament for Buckinghamshire. During his political career, he generally aligned with his family’s political connections until 1801 and after 1806. Between these years, he supported William Pitt the Younger rather than aligning with Charles James Fox, a divergence from many of his Grenville relatives.

Grenville held the office of Lord of the Treasury from March 1782 to March 1783. William Petty, 2nd Earl of Shelburne, offered him positions as Chancellor of the Exchequer or Secretary at War, but he declined both. He was sworn into the Privy Council on 26 December 1783 and served on the Board of Trade from 1784 until his death.

On 20 October 1797, he was elevated to the peerage as Baron Glastonbury. He remained unmarried during his lifetime, and upon his death in 1825, the barony became extinct. His estate was inherited by Thomas Grenville, a noted bibliophile. Additionally, the estate of Butleigh Court was passed to Reverend George Neville of Windsor, a relative who later assumed the additional surname Grenville and became Dean of Windsor.