Young settlement names that look old
Many farm and house names formed in the last ca. 200 years are made with old place name types as a model. For that reason, a name like Højstrup is not necessary 1000 years old; it might have been formed for a newly built farm in the 19th century. Likewise, Hellerup North of Copenhagen does not belong to the old group of torp-names. This name was originally denoting a pleasure property that was named after its owner, J. D. Heller, in the latter part of the 18th century.
Another example is Højsted in Northwest Zealand, which is a village name from 1925. Before that the village was called Rumperup formed by an old male personal name Rumpi and the ending ‑torp. But the villagers found that Rumperup gave bad associations (rumpe means 'behind, bottom' in Danish), and the new name was made up.
Pitfalls
This overview of the most important Danish settlement names, provides a tool to place names in time. For instance it is now possible to ascertain that Hvessinge must be hundreds of years older than Glostrup although Hvessinge actually is a part of Glostup today.
However, many place names have a form in present time that does not immediately reveal from which words the name was originally formed. Some of these corrupt names look like other name types, and some have passed through independent changes. By examining the oldest written sources, it is often possible to see from which endings those names were formed originally.
Examples of this are Grænge on Lolland, which is an inge-name, and Klinting in Vestern Jutland, which is an um-name. Further to that Maglemer on Lolland is a tved-name, Gislev on Funen is originally formed from one word, and Græsted in Northern Zealand originally ended in ‑holt. In other words, a place name is never sure to consist of the words immediately obvious from the present day spelling.