The 40th parallel north is a circle of latitude that is 40 degrees north of the Earth's equatorial plane. It crosses Europe, the Mediterranean Sea, Asia, the Pacific Ocean, North America, and the Atlantic Ocean.

Starting at the Prime Meridian and heading eastwards, the parallel 40° north passes through:

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United States

The parallel 40° north forms the boundary between the State of Kansas and State of Nebraska.On 30 May 1854, the Kansas-Nebraska Act created the Territory of Kansas and the Territory of Nebraska divided by the parallel 40° north.Both territories were required to determine for themselves whether to permit slavery. Open conflictbetween free-stateand pro-slaveryforces in the Kansas Territory led to the American Civil War.

The parallel 40° north formed the original northern boundary of the BritishColony of Maryland. A subsequent royalgrant gave the Colony of Pennsylvanialand north of the 40th parallel but mistakenly assumed it would intersect the Twelve Mile Circle, which it does not. Pennsylvania's border was thus unclear and the colony pushed for a border far south of the 40th parallel. The Mason-Dixon Line was drawn between 1763 and 1767 as the compromise boundary between the overlapping claims of these two colonies.

The parallel 40° north passes through the cities of Philadelphia, Pennsylvania and Columbus, Ohio; as well as northern suburbs of Indianapolis, Indiana and Denver, Colorado.The parallel goes directly through the Port Columbus International Airport, with runway 10L-28R lying immediately north of the line, runway 10R-28L lying slightly south of it, and the line going through the northernmost edges of the terminal.

Baseline Road in Boulder, Colorado traces the parallel 40° north.

See also

• 39th parallel north
• 41st parallel north
• Geological Exploration of the Fortieth Parallel

Co-ordinates
Country, territory or sea
Notes
Mediterranean Sea
Passing just north of the island of Majorca,
Island of Minorca
Mediterranean Sea
Island of Sardinia
Mediterranean Sea
Tyrrhenian Sea
Mediterranean Sea
Gulf of Policastro
Mediterranean Sea
Gulf of Taranto
Mediterranean Sea
Strait of Otranto
Aegean Sea
Kassandra and Sithonia
Aegean Sea
Island of Lemnos
Aegean Sea
Passing just north of Ankara
Passing through Nagorno-Karabakh
Caspian Sea
For about 9 km
Sokh exclave - for about 7 km
Shohimardon exclave - for about 4 km
Yellow Sea
Liaodong Bay
Liaodong Peninsula
Sea of Japan (East Sea)
Mayang Island
Sea of Japan (East Sea)
Island of Honshū
Pacific Ocean
California /> Nevada /> Utah /> Colorado /> Nebraska / Kansas border /> Missouri /> Illinois /> Indiana /> Ohio /> West Virginia /> Pennsylvania /> New Jersey
Atlantic Ocean
Passing just north of Corvo Island, Azores,