Russia and Ukraine share a complicated history that has impacted the culture, politics, and economies of both countries. Ukraine gained independence from the Union of Soviet Socialist Republics (USSR) in 1991. For most of the next decade, the pair maintained generally close ties and good relations. In 2003, Russia and Ukraine signed an agreement defining their 2,000 kilometer (1,240 miles) international frontier, and in 2010, the two States agreed on the process of bilateral demarcation efforts.

In early 2014, however, relations between Ukraine and Russia began to deteriorate. Unrest in Ukraine had increased due to its Russian-aligned government, which resulted in the Revolution of Dignity, or Maidan Revolution, and ultimately the removal of Ukraine’s president, Viktor Yanukovych. The outgoing Ukrainian administration was replaced with a government that supported better relations and increased trade with the European Union.

Russia responded with military action in the Crimean Peninsula, an autonomous region of Ukraine and a strategic location on the Black Sea. Russia had historically leased naval base facilities in the Ukrainian city of Sevastapol on the Crimean Peninsula, which it seized, along with the rest of the territory, in March 2014. Russia’s unilateral annexation was broadly condemned by the international community.

Shortly thereafter, two oblasts in eastern Ukraine declared independence in April 2014. Luhansk and Donetsk, the two states that make up Ukraine’s Donbas region, received no immediate international diplomatic recognition but did receive covert Russian military and economic aid. Ukraine responded with military action and engaged in a conflict with the Russian-backed separatists. Despite multiple attempts to establish a lasting peace and a permanent ceasefire agreement, fighting between Ukrainian military forces and the Russian-backed separatists continued until Russia’s official invasion of Ukraine began in 2022.

In late 2021, Russia began to amass military personnel along the entirety of the frontier with Ukraine. On 21 February 2022, Russia recognized the independence of Luhansk and Donetsk and invaded Ukraine three days later. The international community largely condemned Russia’s invasion, levied economic sanctions against Russia on a much wider scale than previous responses, and provided humanitarian aid, along with limited military support to Ukraine. In October 2022, Russia unilaterally annexed four Ukrainian oblasts, Luhansk, Donetsk, Zaporizhzhia and Kherson. Russia does not maintain de facto control of all the Ukrainian territory that it claims.

The conflict between Russia and Ukraine has continued to the present with no major changes to Russian occupation of eastern Ukraine in the last few years, as the war has become one of attrition. Both States remain active combatants, exchanging small bits of territory and endlessly discussing a ceasefire that has yet to come to reality. The war has had a massive humanitarian cost with more than 16,000 civilian deaths and millions of displaced Ukrainians.

The de jure international boundary between Russia and Ukraine, as defined by a bilateral agreement in 2003, extends from the tripoint with Belarus in the northwest and continues for over 1,000 kilometers (670 miles) before reaching the disputed Donbas region. The disputed land boundary then extends for another 930 kilometers (577 miles) before reaching the waters of the Sea of Azov. The location of the boundary was defined in great detail by the two States in 2003, and while no joint demarcation has occurred, the frontier is visible on the ground for much of its length.

The international boundary between Russia and Ukraine is unstable, especially in the eastern regions adjacent to the disputed territories. De facto control changes frequently as territory is lost and regained by both sides. The military conflict between Russia and Ukraine remains volatile and no attempts to establish even a temporary ceasefire have been effective.