Thomas Atherton Powys, 3rd Baron Lilford (2 December 1801 – 15 March 1861), was a British peer and Whig politician.

Lilford was the son of Thomas Powys, 2nd Baron Lilford, and Henrietta Maria Atherton of Atherton Hall.^[1] He succeeded his father as third Baron Lilford in 1825. From 1826 to 1827 he went on a Grand Tour accompanied by Thomas Henry Lister.They visited Weimar and Jena in June 1826, followed by Leipzig and Dresden. In November they visited Italy, that included a stay in Rome of over three months. Lister returned to England in June 1827 and Baron Lilford remained on at Naples. In 1837 he was appointed a Lord-in-waiting (government whip in the House of Lords) in the Whig administration of Lord Melbourne, a post he held until the government fell in August 1841. He never returned to office.

Lord Lilford married Mary Elizabeth Fox, daughter of Henry Vassall-Fox, 3rd Baron Holland, and Lady Holland, in 1830, and had ten children.^[2] He inherited Lilford Hall in Northamptonshire from his father in 1825. In 1860, he inherited Bank Hall in Bretherton, Lancashire, on the death of his brother-in-law George Anthony Legh Keck. A year after inheriting he died in March 1861, aged 59, and was succeeded by his eldest son Thomas, a prominent ornithologist. Lady Lilford died in 1891.

Coat of arms of Thomas Powys, 3rd Baron Lilford

Crest A lion's jamb couped and erect Gules, holding a staff headed with a fleur-de-lis also erect Or. Escutcheon Or, a lion's jamb erased in bend dexter, between two cross crosslets fitchee in bend sinister Gules. Supporters Dexter, a reaper habited in a loose shirt, leather breeches loose at the knees, white stockings, and black hat and shoes ; in his hat ears of corn, in his right band a reaping-hook, and at his feet a garb, all proper. Sinister, a man in the uniform of the' Northamptonshire yeomanry cavalry, riz. a green long coat, orna-mented on the cuffs and button-holes with gold lace, yellow waistcoat and breeches, and black top boots ; a black stock ; a round hat, adorned with a white feather in front and a green one behind, the sword-belt inscribed with the letters N.Y. and the exterior hand resting on his sword sheathed and point downwards. Motto Parta Tueri (To maintain acquired possessions).[3]