John McMurdo (1743–1803) was a friend of Robert Burns who became the chamberlain to the Duke of Queensberry at Drumlanrig Castle where the poet was a frequent visitor.

[4] As an old Nithsdale family the McMurdos were related to the Sharpes of Hoddam, the Charteris of Amisfield, the Fergussons of Craigdarroch,[3] Dr James Currie[2] and the Duncans of Torthorwald amongst others.

[2] His father was the chamberlain to 'Old Q', the 4th Duke of Queensberry, William Douglas at Drumlanrig Castle to whom he was related as a distant cousin[3] and John, although qualified as a lawyer,[3] succeeded him in 1780,[2] retiring in 1797.

[2][5] McMurdo's daughter Arenta was named in honour of the major commandant of the Royal Dumfries Volunteers, Colonel Arent Schuyler De Peyster.

McMurdo had married De Peyster's wife's sister and towards the end of his life he purchased Mavis Grove and relatives still lived there in the 1860's.

He remained a good friend of Burns until his death and acted as a trustee of the funds raised to assist Jean Armour and her family.

[16] On 26 November 1788 Burns wrote that "I have Philosophy or Pride enough, to support with unwounded indifference against the neglect of my mere dull Superiors, the merely rank and file of Noblesse and Gentry, nay even to keep my vanity quite sober under the larding of their Compliments; but from those who are equally distinguished by their Rank and Character, those who bear the true elegant impressions of the Great Creator, on the richest materials, their little notices and attentions are to me among the first of earthly enjoyments.

"[1] After an embarrassing incident Burns sent letters of apology to those involved, including to McMurdo saying "I believe last night that my old enemy, the Devil, taking the advantage of my being in drink (he well knows he has no chance with me in my sober hours) tempted me to be a little turbulent.

McMurdo was of those associates that Burns sent a copy of the two volume 1793 Edition of his Poems, Chiefly in the Scottish Dialect (Second Edinburgh Edition), remarking in a note that "However inferior now, or afterwards, I may rank as a Poet; one honest virtue, to which few Poets can pretend, I trust I shall ever claim as mine: to no man, whatever his station in life, or his power to serve me, have 1 ever paid a compliment at the expence of TRUTH.

"[17][3] Upon repaying a loan in December 1793[2] of six Guineas and lending McMurdo the sole manuscript copy of the "Merry Muses" Burns wrote in a covering letter that "I think I once mentioned something of a collection of Scots songs I have for some years been making: I send you a perusal of what I have got together.