Yes Baja and Yuatacan Peninsulas are in Mexico. "Baja" is the common name for the Baja California Peninsula, which protrudes from Southern California and runs along north-western Mexico. Some important cities in such peninsula are Tijuana, Ensenada, Mexicali, La Paz and Los Cabos.
Yucatan is the common name for the Yucatan Peninsula, which is located in south-eastern Mexico and touches the Gulf of Mexico as well as the Caribbean Sea. The most important cities in there would be Cancun, Merida, Tulum or Cozumel.
Mexico
It is a peninsula, located in Mexico.
Baja California is a State of Mexico.
The Baja peninsula is part of Mexico.
If you mean the Baja California Peninsula, it is in Mexico. There are other peninsulas in both Mexico and the United States, but "Baja" is the one that causes so much confusion.
Baja California
No, it is a part of Mexico. The peninsula makes up two states in Mexico: Baja California and Baja California Sur
Northwestern Mexico, specifically the Baja California Peninsula.
The Baja California peninsula.
Nearly all the of Baja Peninsula is part of the Sonoran Desert.
Mexico
It is known as the Baja California Peninsula.