​California State Plane Coordinate System

In the United States, the State Plane System was developed in the 1930s and was based on the North American Datum 1927 (NAD27). The California State Plane Coordinate System of 1927, otherwise known as CCS27, is used for defining and stating positions or locations of points on the surface of the earth within the State of California, and the coordinates are based on the foot.  While the NAD-27 State Plane System has been superseded by the NAD-83 System (based on the meter), maps in NAD-27 coordinates are still in use.

In the State Plane Coordinate System, each state has its own zone(s). The number of zones in a state is determined by the area the state covers and ranges from one for a small state such as Rhode Island to as many as seven in California. The projection used for each state is also variable; states that are elongate from east to west, such as New York, use a transverse Mercator projection, while states that are elongate from north to south, such as California, use a Lambert conformal projection (note: Lambert is the name of the cartographer who designed the projection, the projection itself is a conformal conic projection).

Click on each zone to see the names of the counties within that zone

​State Plane/NAD 27 Zones
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7 (Note: in NAD 83, Los Angeles County is consolidated into Zone 5 )