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The Suwałki Gap

The stretch of Poland–Lithuania border, about 100 km long, between Russia’s Kaliningrad exclave and Belarus. It is the only land link between the Baltic states and the rest of NATO and the EU, which has made it one of the most talked-about places in European defence.

Written from cited sourcesLast checked 29 September 2026Suggest a correction

KALININGRADPOLANDLITHUANIABELARUSSuwałkiSejnyRussia tripointBelarus tripoint
Poland–Lithuania borderKaliningrad (Russia) and Belarus shaded, with the Poland–Lithuania border between them.

See it on the globe:Poland →Lithuania →Russia →Belarus →

A narrow bridge of land

The Suwałki Gap is the area around the 104 km land border between Poland and Lithuania, squeezed between Russia’s Kaliningrad exclave to the northwest and Belarus, Russia’s ally, to the southeast.[1] From Kaliningrad to Belarus it is roughly 65 km across.[2] It takes its name from the Polish town of Suwałki, about 30 km from the Lithuanian border.[3]

This strip is the only land link between Estonia, Latvia and Lithuania and the rest of NATO and the EU.[2] Kaliningrad has the mirror-image problem: it is 360 km from mainland Russia, and overland traffic to it depends on railways and roads through Lithuania.[2]

A “volatile point on the world map”

According to RTÉ, the name “Suwałki Gap” was first used in 2015 by Estonia’s president at the time, Toomas Hendrik Ilves, and the same year the US Army’s commander in Europe, General Ben Hodges, called it “one of the most volatile points on the world map”.[3] The fear is a pincer attack from Kaliningrad and Belarus that would cut the three Baltic states off from the rest of NATO.[3]

The ground doesn’t suit tanks: it is hills, forests, lakes, rivers and bog.[3] It is also short of routes, with only two roads and a single railway across it.[2] In 2022 Lithuania and Poland drew up a joint plan for defending the gap, NATO has built up its forces on both sides, and Lithuania plans a new training area near Kapčiamiestis and an upgrade of the Vilnius–Augustów road.[2]

Or a gap that’s overrated?

Not everyone agrees the gap deserves the attention. A 2022 Chatham House paper argued that its border follows no natural feature that gives an attacker an advantage, unlike the Cold War’s Fulda Gap in Germany, and that in a real war long-range weapons would make it closed to both sides anyway.[1] It also pointed out that the danger cuts both ways: Kaliningrad is as exposed to a NATO blockade as the Baltic states are to a Russian one.[1]

Finland’s and Sweden’s entry into NATO has changed the picture too. With them in, the Baltic Sea is almost surrounded by alliance members, and a Polish analyst told RTÉ that this limits the gap’s importance, since the Baltic states could also be supplied by sea and air.[2][3]

An older border story

The area was once part of the Grand Duchy of Lithuania, and after 1918 both new states wanted it. Lithuanian and Polish troops fought in the Sejny Uprising of 1919 and at the Niemen River in 1920, after which the Treaty of Suwałki recognised Punsk, Sejny and Suwałki as Polish. The treaty put Vilnius in Lithuania, but Polish troops took the city two days later and held it until 1939.[4]

A Lithuanian minority still lives on the Polish side: about 80% of the people of Punsk and about 30% of those of Sejny, according to a 2016 count by the Atlantic Council.[4]

Timeline

  1. 1919

    Sejny Uprising

    Polish and Lithuanian forces fight over the area.[4]

  2. 1920

    Treaty of Suwałki

    Punsk, Sejny and Suwałki are recognised as Polish.[4]

  3. 2015

    “The Suwałki Gap”

    Toomas Hendrik Ilves and Ben Hodges warn about the strip.[3]

  4. 2017

    NATO battlegroups

    Multinational battlegroups deploy in Poland and the Baltic states.[3][2]

  5. 2022

    A joint defence plan

    Poland and Lithuania plan together how to defend the gap.[2]

More map oddities

Sources

  1. [1]
  2. [2]
  3. [3]
  4. [4]
    NATO’s Vulnerable Link in Europe: Poland’s Suwalki Gap · Atlantic Council (Agnia Grigas) · 9 February 2016

Map geometry from Natural Earth via world-atlas. See credits.

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