Henry Jones Underwood (1804–1852) was an English architect who spent most of his career in Oxford. He was the brother of the architects Charles Underwood (circa 1791–1883)^[1] and George Allen Underwood (dates unknown).^[2]

Underwood trained in London as a pupil of Henry Hake Seward and then joined the office of Sir Robert Smirke.^[3][4] In 1830 he moved to Oxford where much of his work involved designing churches or schools.^[5] He built Saint Paul's parish church, Walton Street, and the library of the Oxford Botanic Garden in the Greek Revival style but is best known for his Gothic Revival architecture. His church at Littlemore for Newman became a model for other churches.^{[citation needed]}

Underwood designed an extension to Oxford Prison. In 1852 he committed suicide at the White Hart Hotel, Bath, Somerset^[3] so J. C. Buckler completed the extension in his stead.^[6]

• Saint John the Baptist parish church, Summertown, Oxford, 1831 (demolished 1924)^[7]
• Exeter College, Oxford: buildings on Turl Street and Broad Street, 1833-34^[8]
• Pembroke College, Oxford: rebuilding of Wolsey's Almshouses, 1834^[9]
• Saint Mary and Saint Nicholas parish church, Littlemore, Oxfordshire, 1835^[10]
• Botanic Garden, Oxford: library, 1835^[11]
• Saint Paul's parish church, Walton Street, Oxford, 1836 (now Freud's bar)^[12]
• Saint Peter's parish church, Bushey Heath, Hertfordshire, 1836-37^[5]
• Parish church of the Ascension, Littleworth, Vale of White Horse, 1839^[13]
• All Saints' parish church, Llangorwen, 1839^[14]
• Holy Trinity parish church, Lower Beeding, West Sussex, 1840^[5][15]
• Holy Trinity, Burdrop (Sibford Gower), Oxfordshire, 1840^[16]
• Saint Giles' parish church, Horspath, Oxfordshire: rebuilt chancel, 1840^[17]
• Saint Mary's parish, Broughton, Oxfordshire: extension of Rectory, 1842^[18]
• Saint John the Baptist parish church, Bodicote, Oxfordshire: rebuilt church, 1844^[19]
• Saint Mary's parish church, Swerford, Oxfordshire: north aisle, 1846^[20]
• Saint Leonard's parish church, Woodcote, Oxfordshire: rebuilt church, 1846^[21]
• Littlemore Hospital, Littlemore, Oxfordshire: extension, 1847^[22]
• Saint Sepulchre's Cemetery, Oxford: chapel, 1848 (demolished circa 1970)^[23]
• Oxford Prison extension, 1848-56^[24]
• Christ Church Unitarian chapel, Banbury, 1850 (demolished circa 1972)^[25]
• Saint Giles' parish church, Horspath: north aisle and north transept, 1852^[17]

His work also includes Holy Trinity Church, Oxford^{[clarification needed]} and the north aisle of Saint Thomas's parish church, Oxford.^[26] (date uncertain).

• Brodie, Antonia; Felstead, Alison; Franklin, Jonathan; Pinfield, Leslie; Oldfield, Jane, eds. (2001). Directory of British Architects 1834-1914, L-Z. London & New York: Continuum. pp. 855–856. ISBN 0-8264-5514-X.
• Colvin, H.M. (1997). A Biographical Dictionary of British Architects, 1600-1840. New Haven: Yale University Press. pp. 1065–1067. ISBN 0-300-07207-4. (in Google Books)
• Crossley, Alan; Elrington, C.R. (eds.); Chance, Eleanor; Colvin, Christina; Cooper, Janet; Day, C.J.; Hassall, T.G.; Selwyn, Nesta (1979). A History of the County of Oxford, Volume 4. Victoria County History. pp. 369–412. {{cite book}}: |first2= has generic name (help)
• Lloyd, Thomas; Orbach, Julian; Scourfield, Robert (January 2006). Carmarthenshire and Ceredigion. The Buildings of Wales. Yale University Press. p. 42. ISBN 0-300-10179-1.
• Nairn, Ian; Pevsner, Nikolaus (1965). Sussex. The Buildings of England. Harmondsworth: Penguin Books. p. 265. ISBN 0-14-071028-0.
• Pevsner, Nikolaus (1966). Berkshire. The Buildings of England. Harmondsworth: Penguin Books. p. 169.
• Sherwood, Jennifer; Pevsner, Nikolaus (1974). Oxfordshire. The Buildings of England. Harmondsworth: Penguin Books. ISBN 0-14-071045-0.
• Tyack, Geoffrey (1998). Oxford An Architectural Guide. Oxford & New York: Oxford University Press. ISBN 0-19-817423-3.