Lois is surrounded by rocky nooks and crannies in the River Dueñas basin. The name comes from the Latin lutum, meaning mud or clay, indicating that it was situated next to a quagmire or muddy area. It was occupied by the Romans and Goths, who came in search of precious metals such as gold and minium.

Its golden age would come in the 16th century, when it was home to several powerful noble families, who built their palaces there. There were four large estates, each boasting their own stately home or palace. Examples include the 18th century Castañones, owned by Bishop Francisco Castañón, or the Álvarez family palace. Highlights include the church, featuring traces of the Herrerian style of architecture, built in fine materials with impeccable finishes. Visitors can still sense the wealth and prosperity of this town.