In the 19th century, Denmark’s naming practices underwent significant changes. Through legislation in 1828 and 1856, the traditional chain of patronyms was officially broken and the requirement for a fixed (patrilineal) surname introduced for the entire population. At the same time, the usage of middle names (here referring to a name taking the form of a family name but placed between first name(s) and surname in the full onomastic profile) increased. A pilot study of middle names in ten randomly selected areas points to a great regional (and local) divergence in the usage of middle names. The island of Mors in Northern Jutland displays a noticeably higher proportion of women listed with middle names than elsewhere, as well as distinctive combinations of middle name and surname. In this article, this local prevalence of middle names is investigated and compared with the surrounding areas Salling and Thy. With regard to Mors, there is discussion of the impact of naming regulations and of possible connections between middle names and social status. The corpus of names used for the analysis is taken from the Danish census of 1880.