Eastern Ukraine in the context of Dnieper

Between 1441 and 1774, the Crimean Khanate and the Nogai Horde conducted slave raids throughout lands primarily controlled by Russia and Poland–Lithuania. Concentrated in Eastern Europe, but also stretching to the Caucasus and parts of Central Europe, these raids were often supported by the Ottoman Empire and involved the transportation of European men, women, and children to the Muslim world, where they were put on the market and sold as part of the Crimean slave trade and the Ottoman slave trade. The regular abductions of people over the course of numerous incursions by the Crimeans and the Nogais greatly drained Eastern Europe's human and economic resources, consequently playing an important role in the emergence of the semi-militarized Cossacks, who organized retaliatory campaigns against the raiders and their Ottoman backers.

Trading posts in Crimea had previously been established by the Genoese and the Venetians to facilitate earlier Western European slave routes. The Crimean–Nogai raids largely targeted the "Wild Fields" of the Pontic–Caspian steppe, which extends about 800 kilometres (500 mi) north of the Black Sea and which now contains the majority of the combined population of southeastern Ukraine and southwestern Russia.

Donetsk Oblast, also referred to as Donechchyna (Ukrainian: Донеччина, IPA: [doˈnɛtʃːɪnɐ]), is an oblast in eastern Ukraine. Before the 2022 Russian invasion of Ukraine, it was Ukraine's most populous province, with around 4.1 million residents. Its administrative center is Donetsk, though due to the ongoing Russo-Ukrainian War, the regional administration was moved to Kramatorsk. Historically, the region has been an important part of the Donbas region. From its creation in 1938 until November 1961, it bore the name Stalino Oblast, in honour of Joseph Stalin. As part of the de-Stalinization process, it was renamed after the Donets river, the main artery of Eastern Ukraine. Its population is estimated at 4,100,280 (2021 est.).

The oblast is known for its urban sprawl of Donetsk–Makiivka and Horlivka–Yenakiieve and it is often associated with the coal mining industry.

On 6 September 2022, the Armed Forces of Ukraine launched a major counteroffensive against the Russian military during the Russo-Ukrainian war. As Ukraine announced the start of the Kherson counteroffensive in southern Ukraine in late August, Ukrainian forces also began a second counteroffensive in early September in Kharkiv Oblast, in eastern Ukraine.

As the Ukrainian military broke through Russian defensive lines, it recaptured multiple cities in a matter of days. On 7 September, the second day of the counteroffensive, the Ukrainian military advanced over 20 kilometres (12 mi) into Russian-held territory. The next day, Ukraine recaptured Balakliia and Shevchenkove as Russian forces withdrew and fled. On the 9th, Russia began announcing for evacuations in nearby areas as the Ukrainian military continued its advance. The next day, Ukraine retook the key cities of Izium and Kupiansk, securing access to the Oskil River. By the 11th, Ukraine successfully advanced up to 70 kilometres (43 mi) from the pre-counteroffensive front line. In turn, Russia's defence ministry announced the withdrawal of all forces west of the Oskil.

The Cossacks are a predominantly East Slavic, Eastern Christian people, originating from the Pontic–Caspian steppe of eastern Ukraine and southern Russia. Cossacks played an important role in defending the southern borders of Ukraine and Russia, countering the Crimean-Nogai raids, alongside economically developing steppe regions north of the Black Sea and around the Azov Sea. Historically, they were a semi-nomadic and semi-militarized people, who were allowed a great degree of self-governance in exchange for military service under the nominal suzerainty of various Eastern European states. Although numerous ethnic, linguistic and religious groups came together to form the Cossacks, most of them gradually coalesced and Slavicized, thereby adopting East Slavic culture, East Slavic languages and Eastern Orthodox Christianity.

The rulers of the Polish–Lithuanian Commonwealth and Russian Empire endowed Cossacks with certain special privileges in return for the military duty to serve in the irregular troops: Zaporozhian Cossacks were mostly infantry soldiers, using war wagons, while Don Cossacks were mostly cavalry soldiers. The various Cossack groups were organized along military lines, with large autonomous groups called hosts. Each host had a territory consisting of affiliated villages called stanitsas.

The Donetsk People's Republic (DPR; Russian: Донецкая Народная Республика (ДНР), romanised: Donetskaya Narodnaya Respublika (DNR), IPA: [dɐˈnʲetskəjə nɐˈrodnəjə rʲɪˈspublʲɪkə]) is a republic of Russia with a capital in Donetsk, established on an illegally annexed part of Donetsk Oblast, Eastern Ukraine.

The DPR was created by Russian-backed paramilitaries in 2014, and it initially operated as a breakaway state until it was illegally annexed by Russia in 2022.

The Makhnovshchina (Ukrainian: Махновщина, romanized: Makhnovshchyna, IPA: [mɐxˈnɔu̯ʃtʃɪnɐ]) was a mass movement to establish anarchist communism during the Ukrainian War of Independence of 1917–1921. Named after Nestor Makhno, the commander-in-chief of the Revolutionary Insurgent Army of Ukraine, its aim was to create a system of free soviets that would manage the transition towards a stateless and classless society. It controlled territory in southern and eastern Ukraine.

The Makhnovist movement first gained ground in the wake of the February Revolution, when it established a number of agricultural communes in Makhno's home town of Huliaipole. After siding with the Bolsheviks during the Ukrainian–Soviet War, the Makhnovists were driven underground by the Austro-German invasion and waged guerrilla warfare against the Central Powers throughout 1918. After the insurgent victory at the Battle of Dibrivka, the Makhnovshchina came to control much of Katerynoslav province and set about constructing anarchist-communist institutions. A Regional Congress of Peasants, Workers and Insurgents was convened to organise the region politically and economically, with a Military Revolutionary Council being established as the movement's de facto executive organ.

The Ukrainian Ground Forces (SVZSU, Ukrainian: Сухопутні війська Збройних сил України, СВЗСУ, romanized: Sukhoputni viiska Zbroinykh syl Ukrainy), also referred to as the Ukrainian army, is a land force, and one of the eight branches of the Armed Forces of Ukraine. It was formed from Ukrainian units of the Soviet Army after Ukrainian independence, and its ancestry is traced back to the 1917–22 army of the Ukrainian People's Republic.

After the dissolution of the Soviet Union in 1991, Ukraine retained its Soviet-era army equipment. The Armed Forces were systematically downsized and underinvested in after 1991. As a result, the Ukrainian army had very little of its Soviet equipment in working order by July 2014, and most systems had become antiquated. Personnel numbers had shrunk and training, command, and support functions needed improvement. After the start of the war in Donbas in April 2014 in eastern Ukraine, Ukraine embarked on a program to enlarge and modernise its armed forces. Personnel in the Ukrainian Armed Forces overall climbed from 129,950 in March 2014 to 204,000 active personnel in May 2015, with 169,000 soldiers in the Ground Forces branch as of 2016. In 2016, 75% of the army consisted of contract servicemen. Since 2014, Ukraine's ground forces have also been equipped with increasingly modern tanks, APCs, and many other types of combat equipment.

The Seversky Donets (Russian: Се́верский Доне́ц) or Siverskyi Donets (Ukrainian: Сіверський Донець), usually simply called the Donets (Russian: Донец, lit. 'Don + - ets, suffix'), is a river on the south of the East European Plain. It originates in the Central Russian Upland, north of Belgorod, flows south-east through Ukraine (Kharkiv, Donetsk and Luhansk Oblasts) and then again through Russia (Rostov Oblast) to join the river Don, about 100 km (62 mi) from the Sea of Azov. The Donets is the fourth-longest river in Ukraine, and the largest in eastern Ukraine, where it is an important source of fresh water. It gives its name to the Donets Basin, known commonly as the Donbas, an important coal-mining and industrial region in Ukraine.

The Soviet invasion of Ukraine was a major offensive by the Ukrainian Front of the Red Army against the Ukrainian People's Republic (UPR) during the Soviet–Ukrainian War. The invasion was first planned in November 1918, after the Council of People's Commissars of the Russian Soviet Federative Socialist Republic annulled the Treaty of Brest-Litovsk, and was launched in the first days of January 1919, with the occupation of Kharkiv. Its aim was to join Ukraine to the RSFSR, as the country was of significant economic, demographic and strategic importance for the Bolsheviks. In the longer term, the capture of the Black Sea coast was to prevent an intervention by the Allies in support of the Volunteer Army. Finally, the Bolsheviks intended to extend the area they control as far as possible to the west, in order to be able to support the other revolutionary movements in Europe.

In the first days of January 1919, by joining forces with local workers' units, the troops of the 1st Ukrainian Soviet Division [uk] took Kharkiv, which was announced as the seat of the Provisional Workers' and Peasants' Government of Ukraine. Then they quickly captured most of northern and eastern Ukraine, and on 5 February 1919, they occupied Kyiv. The Directorate of Ukraine moved to Vinnytsia, then to Kamianets-Podilskyi. By spring, the Red Army had reached the Zbruch and repelled a counteroffensive by the Ukrainian People's Army (UPA) that threatened Kyiv.

The Kazennyi Torets (Ukrainian: Казенний Торець; Russian: Казённый Торец) is a river in eastern Ukraine. The river travels in the Kramatorsk and Pokrovsk Districts in the Donetsk Oblast, and is a right tributary of the Siverskyi Donets.

Coal mining has historically been an important industry in Ukraine. Although the industry is often associated with the coal-rich Donets basin in the east of the country, other coal mining regions include the Lviv-Volhynian basin and the Dnieper brown coal mining basin. The Donets basin is Ukraine's most developed and largest coal mining region.

In 2013, Ukraine was the third largest coal producer in Europe. In 1976, national production was 218 million metric tonnes. By 2016, production had dropped to 41 million metric tonnes. The Donets Black Coal Basin in eastern Ukraine, with 90% of the nation's reserves, suffers from three connected problems: (1) mines are not profitable enough to sustain capital investment, resulting in aging mining equipment and processes, (2) the government, taking advice from the International Monetary Fund, has discontinued $600 million annual mining subsidies, and (3) the Ukrainian government refuses to buy from mines controlled by Russia.

Malaysia Airlines Flight 17 was a scheduled passenger flight from Amsterdam to Kuala Lumpur that was shot down by Russian-backed forces with a Buk 9M38 surface-to-air missile on 17 July 2014, while flying over eastern Ukraine. All 283 passengers and 15 crew were killed. Contact with the aircraft, a Boeing 777-200ER, was lost when it was about 50 kilometres (31 mi; 27 nmi) from the Ukraine–Russia border, and wreckage from the aircraft landed near Hrabove in Donetsk Oblast, Ukraine, 40 km (25 mi; 22 nmi) from the border. The shoot-down occurred during the war in Donbas over territory controlled by Russian separatist forces in Ukraine.

The responsibility for investigation was delegated to the Dutch Safety Board (DSB) and the Dutch-led joint investigation team (JIT), which in 2016 reported that the aircraft had been downed by a Buk surface-to-air missile launched from pro-Russian separatist-controlled territory in Ukraine. The JIT found that the Buk originated from the 53rd Anti-Aircraft Missile Brigade of the Russian Federation and had been transported from Russia on the day of the crash, fired from a field in a rebel-controlled area, and that the launch system returned to Russia the following day.

The Special Police Forces (Ukrainian: Спеціальні поліцейські сили, romanized: Spetsialni politseiski syly) is a Ukrainian volunteer corps of law enforcement units, part of the Ministry of Internal Affairs of Ukraine. They were formed during the 2014 pro-Russian unrest in Ukraine to strengthen the state’s capacity to maintain public order and security, and were later deployed to Eastern Ukraine as a paramilitary force to fight against Pro-Russian separatists.

The units were primarily composed of volunteers, including former police officers, reservists, and civilians. Similar to the Territorial Defence Battalions, which were under the Ministry of Defence, the Special Police Forces were volunteer formations but fell under the Ministry of Internal Affairs. In addition, many of the units also had links with far-right and nationalist groups. In the first months of the War in Donbas, these volunteer forces took brunt of the fighting.