English, Scottish, and northern Irish: habitational name from any of several places in England and Scotland, variously spelled, that are named with Old English ceald ‘cold’ + well(a) ‘spring, stream’. Caldwell in North Yorkshire is one major source of the surname; Caldwell in Renfrewshire in Scotland another. Possibly also from Caldwell (Warwickshire), Caldwall (Worcestershire), Cauldwell (Bedfordshire, Derbyshire, Nottinghamshire), Caudle Green (Gloucestershire), Caudle Ditch or Cawdle Fen (Cambridgeshire), Chadwell (Essex, Hertfordshire, Leicestershire, Wiltshire), Chardwell (Essex), or Chardle Ditch (Cambridgeshire, early recorded as Kadewelle).

Irish: when not the English surname, this is an Anglicized form of Ó Fuarghuis or Ó hUarghusa ‘descendant of (F)uarghus’, a personal name whose literal sense ‘cold’ + ‘choice’ was reinterpreted as coming from fuaruisce ‘cold water’.

History: Several Caldwells emigrated from Scotland to America by way of Ireland in the 18th century. James Caldwell (1734–81), a son of settler John Caldwell, was born in Charlotte County, VA, and was a militant clergyman during the revolutionary war. Andrew Caldwell, a Scottish farmer, emigrated to North America in 1718 and started a family in Lancaster County, PA. His son David was a Presbyterian clergyman and well-known revolutionary war patriot.