Grensholm, Manor house in Norrköping Municipality, Sweden.

Grensholm is a manor house in Vånga socken, Norrköping Municipality, on the shore of Lake Roxen. Its main building dates probably from the second half of the 17th century and was later remodelled in Carolinian style. It is surrounded by a French-style park with a mirror pond, and the estate includes well-preserved 18th- and 19th-century outbuildings such as a dairy.

The main building dates probably from the second half of the 17th century and was later remodelled in Carolingian style. The estate took its name from the councillor Magnus Gren; through marriages it passed to the Ryning, Rosengren and Ribbing families when Metta Rosengren married Sven Ribbing in 1614, and stayed with them until 1706. The Spens family owned it from 1706 to 1904, when it was sold to Baron Johan Mannerheim.

The name comes from Magnus Gren, a royal councillor; his family later changed the surname to Green. Through marriages the estate passed to the Ryning, Rosengren and Ribbing families when Metta Rosengren married Sven Ribbing in 1614, and stayed with them until 1706. A late-medieval stone building was converted into the estate chapel in the 16th century.

Grensholm lies by Lake Roxen in Vånga parish, Norrköping Municipality. The estate is private: the Lagerfelt family owns it and runs farming and some conference activity there, so the grounds and buildings are not a public sight open at set hours. Contact the estate before planning a visit and ask which parts, if any, can be seen.

Grensholm gave its name to the Grensholm Archive: Gustaf Mannerheim sent his private papers here from the vault of the Bank of Finland between the Winter War and the Continuation War, and later moved the remaining letters and notes here as well, fearing a communist takeover after Prague in 1948. Stig Jägerskiöld used the archive for his Mannerheim biography.