The red-plastered, two-winged main building is perched on a small hill on the northern outskirts of the village Tranekær.

It owes its current appearance to a comprehensive renovation undertaken by the architect Niels Sigfred Nebelong in 1859–1863.

Tranekær traves its history back to Valdemar II (1179–1241), who gave his son, Abel, Langeland and the newly built castle Trænekær.

In 1287, Abel's grandson Valdemar IV of Slesvig handed over Tranekær to his brother Erik Eriksen, whose widow Sophie kept the estate until 1326.

Before his coronation, King John (1455–1513) was fiefholder of Tranekær for a number of years, and after his ascension to the throne in 1455, he ceded it to Queen Christina of Saxony, who ruled over it until her death in 1521.

Queen Sophie Amalie, who was Frederik Ahlefeldt's protector, managed to reconcile Rantzau and the newly married couple.

In 1765, he turned his holdings into a so-called stamhus (family trust) with the effect that they could neither be sold, pledged a divided between heirs.

His nephew Christian Johan Frederik Ahlefeldt-Laurvig, who was the closest heir, considered rejecting the inheritance due to the county's poor finances.

However, he decided to take over the county and shortly afterwards held a public auction at which all the furnishings except the family portraits were put up for sale.

Upon his death in 1865, the county passed to his son Frederik Ludvig Vilhelm Ahlefeldt-Laurvig, who sold most of the tenant farms as freeholdings.