While Russia cemented its control this week over the southern port city of Mariupol after a brutal 12-week assault, the invasion across much of the east has proceeded at a crawl.
With no end in sight, these maps explain how terrain, geography and logistics are shaping the battle for key cities, where the war’s outcome could be decided.
Ukrainians excelled at defending urban and forested areas during the first phase of the war, the drive to take Kyiv. But compared to the northwest, parts of the country’s east are relatively open – especially the plains that extend from Crimea – which makes it harder to defend from advancing tanks.
“It is easy to maneuver,” said Gustav Gressel, senior policy fellow at the European Council on Foreign Relations. It is difficult for Ukraine to fight back “because it’s all flat, all visible.”
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Russian forces have already gained control over a band of land along the coast in the south and are fighting to take the hills above it. But the front lines in the southeast are nearly at a standstill.
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The idea of an easily traversable flatland does not tell the whole story, though.
The terrain isn’t uniform, and some is easier to defend: Towns and small cities dot the northern part of Donetsk, and small rivers and hills run through the area, with forests strung along the Donets River, which flows from Russia. As they did around Kyiv, Ukrainian forces have destroyed bridges, thwarting Russian advances, according to Mason Clark, Russia team lead at the Institute for the Study of War.
Russian forces suffered heavy losses last week when a Ukrainian attack destroyed a pontoon bridge they were using to try to cross the Donets River.
Russia has a deep reservoir of tanks and armored vehicles, but spring rains through June could also create mud that slows them down, according to Dmytro Diadin, an environmental scientist at the OM Beketov National University of Urban Economy in Kharkiv.
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In the Donbas and the Kharkiv regions, up to two-thirds of the land is used for agriculture, according to Diadin. Clusters of trees around farms in northern Donetsk provide cover for Ukrainian forces armed with antitank weapons such as Javelins and NLAWs to ambush Russian convoys, Clark said. Ukrainians have also mined some of the land to funnel Russian forces onto the roads, where they are easier to target, according to Michael Kofman, director of the Russia studies program at CNA, a nonprofit research and analysis organization in Arlington, Va.
The ‘line of contact’
In 2014, separatists supported by Moscow declared “people’s republics” in large parts of Donetsk and Luhansk, along the Russian border. Known as Ukraine’s coal country and industrial center, the mainly Russian-speaking areas had been in Russia’s crosshairs for years.
Extent of Russian advance
A “line of contact” more than 260 miles long divided government-controlled and separatist-controlled areas, rending families and communities. Fighting left more than 14,000 dead between 2014 and early this year.
Ukrainian troops spent eight years building up defenses along the line.
Russian forces have heavily shelled the length of the line of contact in recent weeks, but they have struggled to break past it in Donetsk.
Russia has said it intends to capture all of the Donbas region, the boundaries of which extend well beyond the original line of contact.
Russian forces have made significant progress in Luhansk. At least 90 percent of the region is in Russian hands, according to Clark of the Institute for the Study of War.
Finalizing the capture of the port city of Mariupol this week opened a strategic land bridge from Russia to Crimea, the peninsula Russia annexed from Ukraine in 2014. Russia’s success in Mariupol granted its forces access to a key highway and freed up units to help attack towns in the Zaporizhzhia region.
But Ukraine still holds on to significant chunks of Donetsk. Its forces are “putting up a very stiff resistance,” Pentagon spokesman John Kirby told reporters in early May.
The Institute for the Study of War assessed that as of May 15, the success of Ukrainian defenses in Donetsk, combined with flagging Russian combat power, has likely spurred Russia to shift its focus to capturing the rest of Luhansk, rather than attempting a larger encirclement of Ukrainian troops in Donbas.
A town that had about 45,000 residents, Izyum sits on the Donets River, at the highest point in the Kharkiv region bordering Donetsk. It’s the “gate to Donbas,” a member of the city council told The Post last month. Its position atop a hill grants the forces who control it a sweeping view over roadways and villages nearby.
Russian forces took the town on April 1 after a fierce, three-week fight. Since then, it has served as a springboard for Russian forces trying to push south.
“If the Russians were going to succeed, Izyum would be the most important point” to their Donbas campaign, Clark said.
Russia in April pulled some of its forces from northeastern Ukraine and concentrated them in the Izyum area. But here, the Russians appear to be confined to roads. They have moved down three roadways leading out of Izyum, toward the cities of Slovyansk, Barvinkove and an indeterminate objective farther west, Clark said.
Russian forces reportedly sustained heavy losses in early May along the Izyum axis and have been relatively stalled on the route to Slovyansk.
They’ve made more progress toward Barvinkove, reaching the outskirts of the city. Capturing Barvinkove, about 30 miles southwest of Izyum, would help Russian forces cut off a Ukrainian rail supply line to Slovyansk farther east, according to Kofman.
But a lack of manpower poses a significant constraint for Russia. Ukrainian counterattacks north of Kharkiv exacerbated that problem, forcing Russia to redeploy troops from the Izyum area. Ukrainian officials said Saturday that the country’s forces were launching another counteroffensive near Izyum.
At this point, Russian efforts in the Izyum area may aim to prevent Ukraine from retaking territory, rather than to gain ground, Clark said.
Russia learned to establish firm supply lines the hard way, after logistical issues hampered the first phase of the invasion. In the war in the east, efforts to secure such routes in part explain the crawling speed of the Russian advance.
Russian supply lines to support its operations out of Izyum run from the Belgorod and Valuyki areas in Russia.
lines to Izyum
A Ukrainian counteroffensive this month has driven Russian troops to the Russian border. It’s unlikely that the Ukrainians will be able to sever Russian supply lines imminently, Clark said, but the counterattacks “will certainly be threatening to the Russians.”
The Ukrainian side also has to worry about supplies, even within its own borders, as railway lines have come under Russian attack.
The three cities in Russia’s way
Conquering Donbas, Kofman said, will require that Russia take three key cities: Slovyansk, Kramatorsk and Severodonetsk. “They’re small cities, but they’re cities nonetheless – and they’re not tank country,” he said. That means urban warfare, a Russian weakness.
The cities are near the boundary between Donetsk and Luhansk, close to the Donets River.
Ukrainian forces are concentrated in Severodonetsk and the neighboring city of Lysychansk, and they are trying to hold a line west to the city of Lyman. Russian troops continue to shell and advance slowly toward Lyman.
Capturing the Lyman area could enable Russian forces to advance on Slovyansk from the east, as well as from the Izyum area to the west. Taking Slovyansk would cut off Ukrainian fighters defending against an assault from Severodonetsk, Clark said.
Slovyansk and Kramatorsk are rail hubs, and Kramatorsk has a major hospital. But gaining control of the two cities is “probably beyond [Russia’s] current capabilities, ”Clark said.
As the fighting approached, Ukrainians set up fortified artillery fighting positions in wooded areas around Kramatorsk and dug trenches along country roads.
Russia has enough vehicles and weapons to last through a grinding war, according to analysts, while Ukrainian fighters are nimbler and more motivated, though reliant on foreign weapons.
“This is going to be more of a longer war of attrition, rather than sort of the lightning war that presumably the Russians hoped to achieve,” said Amael Kotlarski, a senior analyst at open-source defense intelligence agency Janes.
Map sources: May 16 territory control data provided by Institute for the Study of War, AEI’s Critical Threats Project. Landcover data via Copernicus program and Global Land Service.
Sammy Westfall and Dalton Bennett contributed to this report.