Mexicali in the context of San Luis Río Colorado

The New River (Spanish: Río Nuevo) flows north from near Cerro Prieto, through the city of Mexicali, Baja California, Mexico, into the United States through the city of Calexico, California, towards the Salton Sea. The river channel has existed since pre-historic times. The river as known today formed from a levee failure and massive flooding that filled the Salton Sea.

The river flow mostly consists of agricultural runoff, municipal discharge and industrial wastewater. The river has been called the most severely polluted river of its size in the United States. Several projects have begun to reduce and mitigate the levels of pollution in the river, including upgrades to sewage treatment infrastructure and enclosure of the river channel.

The Colorado Desert is a part of the larger Sonoran Desert located in California, United States, and Baja California, Mexico. It encompasses approximately 7 million acres (2,800,000 ha; 28,000 km), including the heavily irrigated Coachella, Imperial and Mexicali valleys. It is home to many unique flora and fauna.

Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of Baja California (Territorio Norte de Baja California). It has an area of 70,113 km (27,071 sq mi) (3.57% of the land mass of Mexico) and comprises the northern half of the Baja California peninsula, north of the 28th parallel, plus oceanic Guadalupe Island. The mainland portion of the state is bordered on the west by the Pacific Ocean, on the east by Sonora and the northern Gulf of California, on the north by the United States and on the south by Baja California Sur.

The state has an estimated population of 3,769,020 as of 2020, significantly higher than the sparsely populated Baja California Sur to the south, and similar to San Diego County, California, to its north. Over 75% of the population lives in Mexicali (the state's capital city), Ensenada, or Tijuana (the state's largest city). Other important cities include San Felipe, Rosarito, and Tecate.

The Baja California peninsula (Spanish: Península de Baja California, lit. 'Lower California peninsula') is a peninsula in northwestern Mexico. It separates the Gulf of California from the Pacific Ocean. The peninsula extends from Mexicali, Baja California, in the north to Cabo San Lucas, Baja California Sur, in the south.

With a length of 1,247 km (775 miles), its width ranges from 40 km (25 miles) at its narrowest to 320 km (200 miles) at its widest point and has approximately 3,000 km (1,900 miles) of coastline and approximately 65 islands. The total area of the Baja California peninsula is 143,390 km (55,360 sq mi).

32°25′05″N 115°18′29″W / 32.418°N 115.308°W / 32.418; -115.308

Cerro Prieto (Cocopah: Wee Ñaay, lit. 'Dark Hill') is a volcano located approximately 29 km (18 mi) SSE of Mexicali in the Mexican state of Baja California. The volcano lies astride a spreading center associated with the East Pacific Rise. This spreading center is also responsible for a large geothermal field, which has been harnessed to generate electric power by the Cerro Prieto Geothermal Power Station.

Calexico (/kəˈlɛksɪkoʊ/) is a city in southern Imperial County, California. Situated on the Mexican border, it is linked economically with the much larger city of Mexicali, the capital of the Mexican state of Baja California. It is about 122 miles (196 km) east of San Diego and 62 miles (100 km) west of Yuma, Arizona. Calexico, along with six other incorporated Imperial County cities, forms part of the larger populated area known as the Imperial Valley. First explored by Europeans in the 18th century, Calexico began as a small tent community which was ultimately incorporated in 1908.

On 27 April 2012, a multinational team of television studios staged an airplane crash near Mexicali, Mexico. An unmanned Boeing 727-200, fitted with numerous cameras, crash test dummies and other scientific instruments, was flown into the ground. The exercise was filmed for television.

The Kumeyaay, also known as 'Iipai-Tiipai or by the historical Spanish name Diegueño, is a tribe of indigenous people who live at the northern border of Baja California in Mexico and the southern border of California in the United States. They are an Indigenous people of California.

The Kumeyaay language belongs to the Yuman–Cochimí language family. The Kumeyaay consist of three related groups, the 'Iipai, Tiipai, and Kamia. The San Diego River loosely divided the 'Iipay and the Tiipai historical homelands, while the Kamia lived in the eastern desert areas. The 'Iipai lived to the north, from Escondido to Lake Henshaw, while the Tiipai lived to the south, in lands including the Laguna Mountains, Ensenada, and Tecate. The Kamia lived to the east in an area that included Mexicali and bordered the Salton Sea.