The Suwałki Gap, also known as the Suwałki corridor (), is a sparsely populated area around the border between Lithuania and Poland, and centres on the shortest path between Belarus and the Russian exclave of Kaliningrad Oblast on the Polish side of the border. Named after the Polish town of Suwałki, this choke point has become of great strategic and military importance since Poland and the Baltic states joined the North Atlantic Treaty Organization (NATO).
The border between Poland and Lithuania in the area of the Suwałki Gap was formed after the Suwałki Agreement of 1920, but it carried little importance in the interwar period as at the time, the Polish lands stretched farther northeast. During the Cold War, Lithuania was part of the Soviet Union and communist Poland was a member of the Soviet-led Warsaw Pact alliance. The dissolution of the Soviet Union and the Warsaw Pact hardened borders that cut through the shortest land route between Kaliningrad (Russian territory isolated from the mainland) and Belarus, Russia's ally.
As the Baltic states and Poland eventually joined NATO, this narrow border stretch between Poland and Lithuania became a vulnerability for the military bloc because, if a hypothetical military conflict were to erupt between Russia and Belarus on one side and NATO on the other, capturing the -long strip of land between Russia's Kaliningrad Oblast and Belarus would likely jeopardise NATO's attempts to defend the Baltic states, because it would cut off the only land route there. NATO's fears about the Suwałki Gap intensified after 2014, when Russia annexed Crimea and launched the war in Donbas, and further increased after Russia started a full-scale invasion of Ukraine in February 2022. These worries prompted the alliance to increase its military presence in the area, and an arms race was triggered by these events.
Both Russia and the European Union countries also saw great interest in civilian uses of the gap. In the 1990s and early 2000s, Russia attempted to negotiate an extraterritorial corridor to connect its exclave of Kaliningrad Oblast with Grodno in Belarus. Poland, Lithuania and the EU did not consent. Movement of goods through the gap was disrupted in summer 2022, during the Russian invasion of Ukraine, as Lithuania and the European Union introduced transit restrictions on Russian vehicles as part of their sanctions. The Via Baltica road, a vital sea and road link connecting Finland and the Baltic states with the rest of the European Union, passes through the area. There is an expressway connection from the Polish side, the new S61 expressway, while the A5 highway in Lithuania is being upgraded to a divided highway. The Rail Baltica route near the Suwałki Gap is under construction.
Background
The Suwałki Gap is a sparsely populated region in the north-eastern corner of Poland, in Podlaskie Voivodeship. This hilly area, one of the coldest in Poland, is located on the western margins of the East European Plain. It is crossed by numerous river valleys and deep lakes (such as Hańcza and Wigry), and its vast swathes are covered by thick forests (including the Augustów Primeval Forest) and marshes, such as those in the Biebrza National Park. To its west lies another lake district known as Masuria. The area is relatively poorly developed - there is little industry besides forestry-related facilities, the road network is sparse and the nearest large airport is located several hundred kilometres away; only two major roads (with at least one lane in each direction) and one rail line link Poland with Lithuania. The area is home to some ethnic minorities, particularly Ukrainians, Lithuanians (close to the border with Lithuania) and Russians, but the Russians are sparse on the Polish side.
Poland and Lithuania both gained independence in the aftermath of World War I and started to fight in order to establish control over as much terrain as they could militarily hold. While Lithuania claimed the majority-Polish Suwałki and Vilnius, it ultimately failed to control both. Suwałki was agreed to be part of Poland as a result of the Suwałki Agreement, while Vilnius was captured by Poland in a false flag operation known as Żeligowski's mutiny. In the interwar period, the Suwałki region was a protrusion of Poland into surrounding Lithuania and East Prussia (part of Germany), rather than a gap, and was of little strategic importance.
Following World War II, the vicinity of Königsberg, renamed Kaliningrad shortly after the war, was incorporated as part of the Russian SFSR, part of the Soviet Union, and became a closed area for most of the Soviet era. Lithuania became a Union republic within the USSR, while Poland came under the Soviet sphere of influence and joined the Warsaw Pact. Until the dissolution of the Soviet Union, Poland's only eastern and northern neighbour was the USSR, thus, as in the interwar period, the region mattered little in military terms. This changed after 1991, when Kaliningrad Oblast became a semi-exclave of Russia, sandwiched between Poland and Lithuania, both of which are neighbours with Belarus. Neither borders the "mainland" part of Russia.
Kaliningrad Oblast's neighbours both entered the European Union and the North Atlantic Treaty Organization (NATO). At the same time, only of Polish territory separates two areas of the rival Collective Security Treaty Organisation (CSTO) and the Union State, both of which include Russia and Belarus. The former Estonian President Toomas Hendrik Ilves claims to have come up with the name "Suwałki Gap" before his meeting with Ursula von der Leyen, then serving as the defence minister of Germany, in April 2015 to highlight the vulnerability of the area for the Baltic states.
Civilian interests Russian corridor
The first time a special corridor between Kaliningrad and Belarus (planned to go via Poland) was discussed during a 1990 meeting between Yuri Shemonov, a senior official in Kaliningrad Oblast, and Nikolai Ryzhkov and Mikhail Gorbachev, Premier and President of the Soviet Union, respectively. While Ryzhkov was supportive of the idea, Gorbachev vetoed the proposal, urging the other two men to "stop spreading panic".
After the Soviet Union fell apart, Kaliningrad was cut off from Russia, thus the Russians sought to secure a land transit route from the exclave to mainland Russia through Belarus. After some initial preparations, including signing a treaty which obliged Poland and Russia to open a border crossing near Gołdap, the Russian government announced their intention to build a special "communication corridor" between the checkpoint and Grodno in Belarus, justifying the decision by the region's close economic ties with the country. Russia, which communicated the idea to the Polish side in 1994, additionally sought to bypass Lithuania, with which it had strained diplomatic relations. Initially, the idea sparked little interest, but extensive discussions came in 1996, when Boris Yeltsin, President of Russia, declared he would negotiate with the Polish side to seek permission to build a motorway, citing high transit costs via Lithuania.
Top Polish government officials rejected the proposal. Among the main reasons was the fact that among Poles, the proposal sounded too much like the German request for an extraterritorial link through the Polish Corridor just prior to its 1939 invasion of Poland, and was thus seen as unacceptable. This feeling was amplified by the persistent usage of the word "corridor" among Russian officials. Aleksander Kwaśniewski, then-president of Poland, sounded concerns about the environmental impact of the investment, while some politicians from the then-ruling coalition (SLD-PSL) argued that the corridor would cause a deterioration of diplomatic relations between Poland and Lithuania.
There have been reports that Suwałki Voivodeship, the then local authority for the area in Poland, started talks about the corridor to alleviate its economic problems and even signed an agreement with Grodno Region authorities to promote its construction via a border crossing in Lipszczany, but Cezary Cieślukowski, then-voivode of Suwałki who was seen by the media as supportive of the idea, denied having ever endorsed the proposal, and no proof for that (such as plans or cost estimates) was found in an internal party investigation. When GDDKiA, the Polish agency responsible for the maintenance of main roads, updated its plans for the expressway network in 1996, the proposed link was nowhere to be found.
The topic returned in 2001–2002 when Poland and Lithuania were negotiating accession to the European Union. Russian citizens in Kaliningrad were facing the prospect of having to use passports and apply for visas to cross the border of the new EU member states, which sparked outrage in the Russian press. Therefore, Russia suggested that the European Commission grant a right to a 12-hour free transit for the citizens of the oblast through special corridors in Poland and Lithuania, but this proposal was rejected. Another proposal, with sealed trains, also failed to gain traction; it was ultimately agreed to introduce special permits for Russian citizens travelling to/from Kaliningrad Oblast for transit through Lithuania (but not Poland), known as Facilitated Rail Transit Document (FRTD) and a Facilitated Transit Document (FTD) for rail and road trips, respectively.
Kaliningrad Oblast has since been generally supplied by freight trains transiting through Lithuania. However, on 17 June 2022, in retaliation for Russia's invasion of Ukraine, Lithuania started blocking supplies of sanctioned items to the enclave via road or rail, citing EU's sanction guidance. That guidance was then clarified in a way that exempted rail traffic from the restrictions so long as the volume of deliveries remained within prior consumption volumes, but then Šiaulių bankas, the bank servicing the transit payments, announced it would refuse to accept ruble payments from 15 August and any payments from Russian entities from 1 September.
Transit remains possible via payments to other banks but, in September 2022, was expected to become more burdensome as payments for each freight service will be processed separately to comply with Lithuanian anti-fraud regulator's guidance. Another possibility remains for ships to go from St. Petersburg to Kaliningrad, but this route may be unavailable in winter because the more northerly port may freeze.
EU economic infrastructure The Suwałki Gap hosts several critical corridors because it is the only land route between the Baltic states and the rest of the European Union and NATO.
A strategic communication artery, known in the international E-road network as E67 or as Via Baltica (expressway S61 on the Polish side and A5 highway on the Lithuanian part), passes through the Suwałki Gap. It is part of the North Sea-Baltic Corridor (previously the Baltic-Adriatic Corridor), one of the core routes of the Trans-European Transport Network (TEN-T) that connects Finland and the Baltic states with the rest of Europe. As of June 2025, the Polish expressway is completed; the only segment not fully open yet is the bypass of Łomża, expected to be unveiled in September 2025. On the Lithuanian side, most of the A5 highway is upgraded to a dual highway with grade-separated junctions. The last section of the motorway, that close to the border is slated to be completed by late 2025.