Principal meridian

This line is exactly ten miles west of the Red River at the Canada–United States border.

Six other meridians were designated at four-degree intervals westward, with the seventh located in British Columbia; the second and fourth meridians form the general eastern border and the western border of Saskatchewan.

In the United States Public Land Survey System, a principal meridian is the principal north–south line used for survey control in a large region, and which divides townships between east and west.

Baseline Road or Base Line Street extends for about 40 miles (64 km) from Highland, California east of San Bernardino to La Verne, California where it meets Foothill Boulevard.

You can help Wikipedia by expanding it.This article about geography terminology is a stub.