Turco-Iranian Border Change,
1932-1937.
During the 1920’s, talks between Iran and Turkey over redefining their
shared border (which was first defined in the Constantinople Protocol of
1913) due to border disputes and the aftermath of the Ararat Rebellion
(1927–1930) occurred. This came to ahead when in 1932, the Tehran
Convention took place, leading to Iran and Turkey exchanging territory.
Due to an error with the map that was used to delimit the new border, a
tiny rectification occurred in 1937 under the Tehran Agreement to
correct the mistake. The new border was finally ratified by both sides
in 1939 and it has not changed since.
by u/AoifeIves