40th parallel north

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

Country, territory or sea	Notes

Mediterranean Sea
	Island of Minorca
Mediterranean Sea
	Island of Sardinia
Mediterranean Sea	Tyrrhenian Sea

Mediterranean Sea	Gulf of Taranto

Mediterranean Sea	Strait of Otranto


Aegean Sea	Including the Kassandra and Sithonia peninsulas, and the island of Lemnos ()


	Including Nagorno-Karabakh
Caspian Sea






	Sokh exclave surrounded by

	Shakhimardan exclave surrounded by


Yellow Sea	Liaodong Bay
	Liaodong Peninsula

Sea of Japan
	Island of Honshū
Pacific Ocean
	California Nevada Utah Colorado Nebraska / Kansas border Missouri Illinois Indiana Ohio West Virginia Pennsylvania New Jersey
Atlantic Ocean

The parallel 40° north forms the boundary between the State of Kansas and State of Nebraska. On May 30, 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 conflict between free-state and pro-slavery forces in the Kansas Territory led to the American Civil War.

The parallel 40° north formed the original northern boundary of the British Colony of Maryland. A subsequent royal grant gave the Colony of Pennsylvania land north of the parallel 39° north. 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