37th parallel north

[1] The 37th parallel north is roughly the northern limit of the visibility of Canopus, the second-brightest star of the night sky.

Along with the 37th parallel south, it is the latitude at which solar irradiance is closest to the planetary average,[2] with higher solar irradiance equatorward and lower poleward.

Starting at the Prime Meridian and heading eastward, the parallel 37° north passes through: In the United States, the parallel defines the southern borders of Utah, Colorado, and Kansas, and the northern borders of Arizona, New Mexico, and Oklahoma.

Congress extended the line west to New Mexico Territory, thus defining which states and territories would constitute The South between the Colorado and Mississippi Rivers, and creating what later became the Oklahoma Panhandle.

[3] The parallel 37° north formed the southern boundary of the historic and extralegal Territory of Jefferson.