[1] His father was Abraham Lehn (1701–1757), an estate owner and collector of books and art.
At the death of an uncle Johan Lehn in 1760, he received the Fyn estates Hvidkilde, Nielstrup and Lindskov.
[2] Poul Abraham Lehn created the Barony of Guldborgland from his holdings at Berritzgaard and the purchase of Orebygaard in 1775, combining all of his possessions northwest of Sakskøbing.
In 1803, Højbygaard and Lungholm were converted into an entailed estate (stamhus) under the name Baroniet Sønderkarle for his daughter, Johanne Frederikke Lehn, whose husband was Frederik Wallmoden of Fuglsang Manor.
The legal effect of a stamhus was that the estate could neither be sold, mortgaged or divided between heirs.