Baja California is the northernmost state of Mexico. It has an area of 71,576 km² (27,636 sq mi), or 3.57% of the land mass of Mexico and comprises the northern half of the Baja California peninsula, north of the 28th parallel. The state is bordered on the west by the Pacific Ocean, on the east by Sonora, the U.S. State of Arizona, and the Gulf of California (also known as the Sea of Cortez), and on the south by Baja California Sur. Its northern limit is the U.S. state of California.
Baja California is the twelfth state by area in Mexico.

Its geography ranks from beaches to forests and deserts. The backbone of the state is the Sierra de Baja California; where the Picacho Del Diablo, the highest point of the peninsula, is located.

This mountain range effectively divides the weather patterns in the state. In the northwest, the weather is semi-dry, mediterranean.

In the narrow center, the weather changes to be more humid due to altitude.
It is in this area where a few valleys can be found, such as the Valle de Guadalupe, the major wine producer area in Mexico. To the east of the mountain range, the Sonoran Desert dominates the landscape. In the south, the weather becomes drier and gives place to the Vizcaino Desert. The state is also home to numerous islands in both of its shores. In fact, the westernmost point in Mexico, the Guadalupe Island, is part of Baja California. The Coronado, Todos Santos and Cedros Islands are also on the Pacific Shore. On the Gulf of California, the biggest island is the Angel De La Guarda, separated from the peninsula by the deep and narrow Canal de Ballenas.

The state's inhabitants are known as "Cachanillas," after the wild cachanilla plant which has a fresh aroma and was used by the original inhabitants to make huts. Originally, the term "Cachanillas" was applied only to the inhabitants of the Mexicali Valley, although there are tales of the term being used for inhabitants of Santa Rosalía in Baja California Sur.
Baja California has two sea shores. It borders the Pacific Ocean to the west and the Gulf of California to the east. Even though the state is not large in area, its geography is very diverse. The Sierra de Baja California (also known as the Peninsular Ranges) runs in the middle of the state with different denominations. The two most important are the Sierra de Juarez and the Sierra de San Pedro Martir. These ranges are home to forests similar to those in Southern California. The Picacho del Diablo is the highest peak in the whole peninsula, offering spectacular views of the Gulf of California. Between these mountain ranges, some valleys are suitable for agriculture such as the Valle de Guadalupe and the Valle de Ojos Negros. The mild weather makes this area excellent for the production of citrus fruits and grapes. This area is also rich in minerals. The mountain range gets closer to the Gulf of California towards the south of the state and the western slope becomes wider, forming the Llanos del Berrendo in the border with Baja California Sur.

The cool winds from the Pacific Ocean and the cold California Current make the weather along the northwestern coast pleasant year round. The coastal cities of Playas de Rosarito and Ensenada have the one of the nicest weather patterns in the whole Mexico. But due to the California current, rains from the north barely reach the peninsula and this makes the weather drier towards the south. South of El Rosario river, the area becomes a desert. This desert, however, is rich in succulents such as the Cardon, Boojum tree, Ocotillo and others. These plants can flourish in part due to the coastal fog. Driving along MX-1 provides a good view of this area.