This unusual surname may have three origins: patronymic, topographic and descriptive. (1) It may originate from a person who lived at Erpe, or a similar named place. There appear to be two places in this category: Erp, in Netherlands ands Ypres, in Belgium. The latter was brought into Britain early by William de Ypres, chief lieutenant of King Stephen, of England (reigned 1135-1141). This surname is found with the 'p' preceding and succeeding the 'r,' particularly in France. The Ypres origin may sometimes be found as d'Ipres, Dipres and variants thereof. There are places in the British Isles that have taken their name from Ypres. (2) The lack of any suffix to some early examples of the surname suggests it may be descriptive. In this case it would come from the Old English, 'earp,' which in turn comes from the Anglo-Saxon 'eorp,' meaning 'swartthy' - of a dark complexion. (3) It may originate from from a Brythonic forename: 'Erp,' in Gaelic, or, 'Yrp,' in Welsh. Since neither appear to have been used since The Conquest (1066), it is an unlikely origin.

The surname and its variants are found throughout the English-speaking world, France, Belgium, the Netherlands and to a lesser degree - other European states.

• 1157. Rd[ard]. le Yrpe (Tideswell, Derbyshire): The Feudal History of the County of Derby
• 1252. Willielmo de Erpe: The History of the Antient Abbeys, Monasteries, Hospitals, Cathedral and Collegiate Churches
• 1301. John Yrp, of Gunthorp: Northamptonshire Tax Assessment
• 1333. John Irp (Norfolk): Ipswich Borough Archives
• 1361. John de Ypre, sherrif of Lancashire: A Topographical, Statistical, & Historical Account of the Borough of Preston
• 1367. John Dipre: Calendar of the Patent Rolls
• 1370. Johes de Ipre, member of Parliament (Lancashire): History of the County Palatine and Duchy of Lancaster
• 1377. John de Ipres, steward of the household: Calendar of Inquisitions Miscellaneous
• 1389. Reginald de Irpe (Droghda, Ireland): Calendar of the Patent Rolls
• 1486. John Irpe (Burton-on-Tren, Staffordshire): Descriptive Catalogue of the Charters & Muniments of the Gresley Family
• 1573. 'George Carleton granted to John Yrpe, yeoman': Survey of London, vol. 20
• 1607. John Van Erpe, of London, a foreign merchant: Calendar of the Cecil Papers, vol 24
— Forebears.io

I cannot suggest any derivation of this name.

1561. William Erpe and Elizabeth Brett: Marriage Lic. (London).

1809. Married — William Kendrick and Mary Erpe: St. George, Hanover Square.

ERP: A common personal name in Pictland. Erp, Yrp appears as the name of a Welsh king by itself in Liber Llandavensis (p. 72), and also compounded in Urb-gen (Nennius), afterwerds written Urien. The name was borrowed from the Picts by the Norsemen and gave name to the Icelandic family of Erplingi. Erp, son of Meldun, a Scots earl, was captured by the Norsemen, and as a freedman, went to colonize Iceland in the end of the ninth century (Landnambok, II, 16, 17). Ere is the Gaelic equivalent of the same.