The Laguna Madre extends well into Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, to the mouth of the Río Soto la Marina in the state of Tamaulipas

Tamaulipas

Tamaulipas officially Estado Libre y Soberano de Tamaulipas is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 43 municipalities and its capital city is Ciudad Victoria. The capital city was named after Guadalupe Victoria, the...

. It is separated from the Gulf of Mexico on the east by a number of barrier islands, including Barra Los Americanos, Barra Jesús María, and Barra Soto la Marina, and is bounded on the west by mainland Tamaulipas. It is located in the municipalities of Matamoros

Matamoros, Tamaulipas

Matamoros, officially known as Heroica Matamoros, is a city in the northeastern part of Tamaulipas, in the country of Mexico. It is located on the southern bank of the Rio Grande, directly across the border from Brownsville, Texas, in the United States. Matamoros is the second largest and second...

, San Fernando

San Fernando, Tamaulipas

San Fernando is a municipality and city located in the Mexican state of Tamaulipas.-Massacres:San Fernando, Tamaulipas is notorious for experiencing two of the largest recorded massacres of the Mexican Drug War...

, and Soto la Marina

Soto la Marina Municipality

Soto la Marina Municipality is one of the municipalities of Tamaulipas. The seat is at Soto la Marina, Tamaulipas....

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The Laguna Madre is very shallow, with an average depth of only 0.9 m.