Nicholas Saunderson, 1st Viscount Castleton (1562–1631) was an English landowner and politician who sat in the House of Commons in 1593 and 1625.
He was educated at Oxford University, being awarded BA in 1579, and also entered Lincoln's Inn in 1579.
He succeeded to the estates of Saxby and Fillingham at the age of 21 on the death of his father and became one of the leading landowners of Lincolnshire.
[1] In 1593, Saunderson was elected Member of Parliament for Great Grimsby, a seat which his uncle Thomas Grantham had held until his death.
He lived in style and employed the musician Giles Farnaby to teach his children.