Oscar Ambrosius Castberg (30 September 1846 – 18 June 1917) was a Norwegian painter and sculptor.
[2] His father, physician Tycho Fredrik Edvard Castberg, was the oldest living son of priest and politician Peter Hersleb Harboe Castberg.
[3] Oscar Ambrosius Castberg first tried his luck at sea, but gave this up due to problems with seasickness.
Instead, he took a sculptor's education, studying with a public grant[3] under Julius Middelthun in Christiania and Jens Adolf Jerichau in Copenhagen.
He took up landscape painting on a naturalistic basis with motifs principally from Kristiania and the surrounding area.