Lancaster Name Meaning and History
English: habitational name from Lancaster in northwestern England, named in Old English as ‘Roman fort on the Lune’, from the Lune river, on which it stands, + Old English cæster ‘Roman fort or walled city’ (Latin castra ‘legionary camp’). The river name is probably British, perhaps related to Gaelic slán ‘healthy’, ‘salubrious’.
Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4
http://www.ancestry.com/facts/Lancaster-family-history.ashx
Lancaster Name Meaning and History
This name is of Anglo-Saxon origin, and is locational from the English city in Lancashire thus called. The name was spelt "Loncastre" in the Domesday Book of 1086 and "Lanecastrum" in the 1094 Pipe Rolls of that county. The first element of the name derives from the river "Lune" on which the city stands, plus the Olde English pre 7th Century "ceaster", a Roman fort. The surname from this source is first recorded in the latter half of the 12th Century (see below). One Edmund, Earl of Lancaster (1245 - 1296) called "Crouchback", the second son of Henry 111 and Eleanor of Provence was styled King of Sicily by the Pope in 1255 and renounced this claim in 1263, and is buried in Westminster Abbey. In 1327, one John de Lancaster appears in the Subsidy Rolls of Cambridgeshire. Other spellings of the name have included: de Langcastre (Essex, 1327), Longcaster (Yorkshire, 1494) and Lankester (Suffolk, 1565). On July 4th 1635, one Gowen Lancaster, aged 28 yrs., embarked from London on the ship "Transport" bound for Virginia. He was one of the first recorded namebearers to enter America. Joseph Lancaster (1778 - 1838) found the Lancasterian system of education; he founded a Free School for a thousand boys in 1801. The first recorded spelling of the family name is shown to be that of William de Lonecastre, which was dated 1175, in the "Cartulary of Staffordshire", during the reign of King Henry 11, known as "The Builder of Churches" 1154 - 1189. http://www.surnamedb.com/Surname/Lancaster#ixzz1G3PgzQkF
If any descendants of Edmund Crouchback still use the name of Lancaster, or something similar, then this is probably in Spain, Portugal or Latin America, because two daughters of John of Gaunt, who married Edmund's descendant Blanche and effectively became leader of the Lancaster faction of the Royal Family, married there and are thought to have passed the name on.
In Britain the name was already widely in use before Edmund Crouchback by more common families. The easiest family to trace, and sometimes thought to be the earliest true users of Lancaster as a family name, were the descendants of William son of Gilbert, who possessed what became the Barony of Kendal amongst other things. Many families who use the surname today may descend from him, or an ally of his family. Concerning his ancestry the only things we can say with any confidence are that he called Ketel son of Ethelred his uncle (avunculus) and that his grand daughter said that he had used the name Taillebois, before taking up the name Lancaster.
http://www.surnamedb.com/Surname/Lancaster#ixzz1G3PsB7Dc
My great uncle Frank Lancaster mentioned the Barons of Kendal to me. One of my ancestors was christened Lancaster Lancaster-I'd like to know how that came about. http://www.surnamedb.com/Surname/Lancaster#ixzz1G3PzisBS
If this is your family this may be just what you are looking for but you should try to verify these postings with documents to be certain they are your ancestors.