The Turkish-Syrian border was first drawn in 1921, altered in 1938, and finally demarcated once again in 1956. Between 1991 and 1993, portions of the border were further demarcated, bringing the border deeper into Turkish territory. Most of the land in near the Turkish-Syrian border falls under the legal category of "Forbidden Military Zone in the First and Second Degrees" (i.e., public land administered by the Turkish military). Some of it is formerly privately-owned farmland nationalized during the 1956 demarcation.
"Turkey Moves Forward to Demine Upper Mesopotamia,"
Journal of Mine Action
: Vol. 8
, Article 21.
Available at: https://commons.lib.jmu.edu/cisr-journal/vol8/iss2/21