The Lomonosov Ridge (Russian: Хребет Ломоносова) is an unusual underwater ridge of continental crust in the Arctic Ocean. It spans 1800 km from the New Siberian Islands over the central part of the ocean to Ellesmere Island of the Canadian Arctic Archipelago. The width of the Lomonosov Ridge varies from 60 to 200 km. It rises 3,300 to 3,700 m above the seabed. The minimum depth of the ocean above the ridge is 954 m. Slopes of the ridge are relatively steep, broken up by canyons, and covered with layers of silt.
The Lomonosov Ridge was first discovered by the Soviet high-latitude expeditions in 1948 and is named after Mikhail Lomonosov. The name was approved by the GEBCO Sub-Committee on Undersea Feature Names (SCUFN). 
In the 2000s, the geological structure of the ridge attracted international attention due to a 20 December 2001 official submission by the Russian Federation to the UN Commission on the Limits of the Continental Shelf in accordance with the United Nations Convention on the Law of the Sea (article 76, paragraph 8). The document proposed establishing new outer limits for the Russian continental shelf, beyond the previous 200-mile (320 km) zone, but within the Russian Arctic sector. The territory claimed by Russia in the submission is a large portion of the Arctic reaching the North Pole. One of the arguments was a statement that the underwater Lomonosov Ridge and Mendeleev Ridge are extensions of the Eurasian continent. In 2002 the UN Commission neither rejected nor accepted the Russian proposal, recommending additional research.
Danish scientists hope to prove that the ridge is an extension of Greenland which would make Denmark another claimant to the area. Canada, another claimant, asserts that the ridge is an extension of its continental shelf. In April 2007, Canadian and Russian scientists were sent to map the ridge as a possible precedent for determining sovereignty over the area. In late June 2007, Russian scientists claimed that the ridge is an extension of Russia's territory.
Arktika 2007 Expedition
In late July 2007, a Russian expedition sent an icebreaker and two mini-submarines, Mir-I and Mir-II, to explore the region. Russian scientists dived down 4261 m (14,000 ft) below the surface and on 2 August planted a rust-proof titanium metal Russian flag on the seabed.  In April 2007, Canada and Denmark, which both claimed part of the ridge, were also mapping it under the polar ice, Canada's CBC reported.
As a follow-up in mid-September 2007, Russia's Natural Resources Ministry issued a statement:
Preliminary results of an analysis of the earth crust model examined by the Arctic-2007 expedition, obtained on 20 September, have confirmed that the crust structure of the Lomonosov Ridge corresponds to the world analogues of the continental crust, and it is therefore part of the Russian Federation's adjacent continental shelf.
- CBC News. Broken ship halts Russian expedition to claim Arctic seabed. 25 July 2007. Retrieved 25 July 2007.
- "IHO-IOC GEBCO Gazetteer" (PDF). International Hydrographic Organization/Intergovernmental Oceanographic Commission. September 2007. Retrieved 24 May 2008.
- Outer limits of the continental shelf beyond 200 nautical miles from the baselines: Submissions to the Commission: Submission by the Russian Federation CLCS. United Nations
- Area of the continental shelf of the Russian Federation in the Arctic Ocean beyond 200-nautical-mile zone - borders of the 200 mile zone are marked in red, territory claimed by Russia is shaded
- Denmark hopes to claim the North Pole BBC News, 5 October 2004. Retrieved 10 November 2006.
- Kremlin lays claim to huge chunk of oil-rich North Pole The Guardian, 28 June 2007. Accessed 3 July 2007.
- BBC News: Russia plants flag under N Pole
- Mapping continues along the Lomonosov Ridge – SikuNews, 17 April 2007.Retrieved on 2007-08-07
- "Lomonosov Ridge, Mendeleyev elevation part of Russia's shelf - report". Interfax Moscow. 20 September 2007. Retrieved 21 September 2007.[dead link]