Puerto Peñasco (O'odham: Geʼe Ṣuidagĭ) is a city located in Puerto Peñasco Municipality in the northwest of the Mexican state of Sonora, about 100 km from the border with the U.S. state of Arizona. It is located on the small strip of land that joins the Baja California Peninsula with the rest of Mexico. The area is part of the Altar Desert, one of the driest and hottest of the larger Sonora Desert. Because of the lack of water, this area had no permanent settlements until the 1920s. In the 1930s and 1940s, the construction of a rail line connecting Baja to the rest of Mexico passed through and allowed for the development of a permanent town. For most of its history, the area has been associated with fishing, which is still a major source of income. However, since the 1990s, there has been a push to develop the area for tourism, as it is already heavily visited by people from Arizona and California.