Spain-Andorra: none identified

Spain-France: none identified

Spain-Gibraltar (UK): in 2002, Gibraltar residents voted overwhelmingly by referendum to reject any "shared sovereignty" arrangement; the Government of Gibraltar insists on equal participation in talks between the UK and Spain; Spain does not recognize British sovereignty beyond the original fortified perimeter of the city and disapproves of UK plans to grant Gibraltar greater autonomy; after voters in the UK chose to leave the EU in a June 2016 referendum, Spain again proposed shared sovereignty of Gibraltar; UK officials rejected Spain’s joint sovereignty proposal

Spain-Morocco: Morocco protests Spain's control over the coastal enclaves of Ceuta, Melilla, and the islands of Penon de Velez de la Gomera, Penon de Alhucemas, and Islas Chafarinas, and surrounding waters; both countries claim Isla Perejil (Leila Island), which remains unoccupied but was the site of a  military standoff in 2002; Morocco serves as the primary embarkation area for illegal migration into mainland Spain from North Africa

Spain-Portugal: Portugal does not recognize Spanish sovereignty over the territory of Olivenza based on a difference of interpretation of the 1815 Congress of Vienna and the 1801 Treaty of Badajoz

US-Antarctica: the US has made no territorial claim in Antarctica (but has reserved the right to do so) and does not recognize the claims of any other states

US-Bahamas: the Bahamas and US have not been able to agree on a maritime boundary; the two countries have met several times to define their maritime boundary

US-Canada: Canada and the United States dispute how to divide the Beaufort Sea and the status of the Northwest Passage but continue to work cooperatively to survey the Arctic continental shelf; because of the dispute over Machias Seal Island and adjoining North Rock, the terminus of the land boundary beyond Canada's Grand Manon Island and the US state of Maine is not defined

US-Canada-Mexico: the US has intensified domestic security measures and is collaborating closely with its neighbors, Canada and Mexico, to monitor and control legal and illegal personnel, transport, and commodities across the international borders

US-Cuba: the US Naval Base at Guantanamo Bay is leased from Cuba and only mutual agreement or US abandonment of the area can terminate the lease

US-Haiti: Haiti claims US-administered Navassa Island; the dispute dates to 1857, when the US claimed the Navassa Island under the 1856 Guano Act; Haiti claims it has had ownership over Navassa Island continuously since its 1801 constitution laid claim to “adjacent lands”

US-Marshall Islands: in May 2016, the Marshall Islands filed a declaration of authority with the UN over Wake Island, which is currently a US territory, reaffirming that it considers Wake Island part of its territory; control over Wake Island would drastically increase the Marshall Islands’ exclusive economic zone; the US State Department is assembling a group of experts from both countries to discuss the maritime boundary

US-Russia: 1990 Maritime Boundary Agreement in the Bering Sea still awaits Russian Duma ratification

US-Tokelau: Tokelau included American Samoa's Swains Island among the islands listed in its 2006 draft constitution; Swains Island has been administered by American Samoa since 1925; the 1980 Treaty of Tokehega delineates the maritime boundary between American Samoa and Tokelau; while not specifically mentioning Swains Island, the treaty notes in its preamble that New Zealand does not claim as part of Tokelau any island administered as part of American Samoa

Turkmenistan-Azerbaijan: in January 2021, the two countries reached a preliminary agreement on the joint exploration of an undersea hydrocarbon field containing oil and natural gas in the Caspian Sea

Turkmenistan-Iran: none identified

Turkmenistan-Kazakhstan: Kazakhstan and Turkmenistan signed a treaty on the delimitation and demarcation process in 2001; field demarcation of the boundaries with Kazakhstan commenced in 2005; Turkmenistan and Kazakhstan agreed to their border in the Caspian Sea in 2014

Turkmenistan-Kazakhstan-Uzbekistan: in 2017, the three countries signed an agreement of the junction of their borders

Turkmenistan-Uzbekistan: cotton monoculture in Uzbekistan and Turkmenistan creates water-sharing difficulties for Amu Darya river states; in 2021, the two countries reached an agreement to create a joint intergovernmental commission to oversee water management