The San Remo Conference assigned the League of Nations mandates for Syria and Lebanon to France and Palestine/Mesopotamia to Britain, establishing the international framework within which later Jordan–Syria frontier work would occur.
Britain and France signed an Anglo-French convention (often grouped among the Franco-British Boundary Agreements) laying down, in broad terms, a frontier between their mandated territories; later work found parts of the Syria–Transjordan line difficult to apply on the ground, prompting revision and field delimitation.
The League of Nations approved the memorandum defining Transjordan as the area east of the Palestine mandate’s core, formalizing Transjordan’s administrative status under the British mandate system—an essential precursor to later fixing its northern (Syria-facing) frontier.
Britain and France approved the Paulet–Newcombe Agreement, following boundary-commission work, refining earlier arrangements by fixing much of the Syria–Palestine mandate boundary. While not the Jordan–Syria line, it anchored adjacent mandate borders and reflected the same commission-based approach later used for the Transjordan–Syria frontier.
A protocol was signed by the relevant British and French mandatory authorities agreeing on a modified frontier between Syria and Transjordan, subject to League of Nations approval, and providing for delimitation on the ground by a commission (as contemplated by the 1920 convention).
The League of Nations Council approved the 31 October 1931 protocol establishing a modified Syria–Transjordan line, described in contemporary reporting as aiming to avoid disrupting local rights and customs and to facilitate administration and communications.
With the end of the British mandate and independence as the Hashemite Kingdom of Transjordan (later the Hashemite Kingdom of Jordan), the previously mandated boundary with Syria functioned increasingly as an international border between sovereign states.
A deadly incident at the Ramtha checkpoint—reported as a mine explosion involving a vehicle arriving at the Jordan–Syria border post—triggered a sharp diplomatic rupture, including expulsions, highlighting ongoing sensitivity and security volatility along the frontier.
The U.S. Department of State’s Office of the Geographer published International Boundary Study No. 94: Jordan–Syria Boundary, summarizing the boundary’s course and the principal instruments underpinning it—an influential technical reference for the border’s documentary basis.
During Jordan’s 1970 internal conflict, Syrian forces crossed into northern Jordan in support of Palestinian factions and advanced toward areas near Irbid before withdrawing. The episode became a major Jordan–Syria border crisis and later informed efforts to stabilize and clarify frontier management.
Jordan and Syria announced an in-principle understanding to redraw/regularize segments of the border, framed publicly as a move back toward the 1931 demarcation, addressing areas of alleged encroachment and laying groundwork for a formal settlement.
Jordan and Syria signed a border pact to settle a longstanding dispute through land exchanges, addressing Jordan’s claim of Syrian encroachment (reported as about 125 km²) and a smaller Jordanian presence inside Syria (about 2.5 km²), and pairing border settlement with broader cooperation accords.
Jordan–Syria frontier formation, commissions, and adjustments (1920–1974)
