Which peninsula forms the southern part of mainland Baja California in Mexico?

The Baja California Peninsula forms the southern part of mainland Baja California in Mexico.

It extends roughly 1,200 kilometres southward from the United States–Mexico border between the Pacific Ocean and the Gulf of California. Mexico’s states of Baja California and Baja California Sur occupy the peninsula, with the Gulf of California separating it from mainland Mexico.

The peninsula contains several important mountain ranges, including the Sierra de Juárez, Sierra de San Pedro Mártir and Sierra de la Giganta. Its landscapes range from dry desert and coastal scrub to high-elevation pine forests. The region is also known for gray whale breeding lagoons on the Pacific coast.

The peninsula is often confused with the state of Baja California, but the geographic landform includes both Mexican states. Cabo San Lucas lies at the southern tip, where the Pacific Ocean meets the Gulf of California.