Tamaulipas (formerly Nuevo Santandcr), an E. state of Mexico, bounded N. by Texas, E. by the gulf of Mexico, S. by Vera Cruz, and W. by San Luis Potosi and Nuevo Leon; area, 28,-059 sq. m.; pop. in 1871, 108,778. The coast is low and sandy, and several lagoons extend along the shore, the largest being the laguna Madre, more than 100 m. long, and in some places 20 m. wide. The Rio Grande del Norte forms the northern boundary line; other rivers are the Fernando or Tigre, Borbon, Santander, and Tampico; the mouths of all are so much encumbered with bars that they are almost useless for navigation. In the northern part of the state the flat country extends inland for some distance, and the surface then rises into elevated plains; but in the south it is diversified by numerous mountains and fine valleys. During the hot season the climate on the coast is unhealthful, but in the elevated parts of the interior it is temperate and agreeable. There are rich silver and copper mines, but they are little worked. The forests abound in valuable timber. Much of the soil is very fertile, and the grains, vegetables, and fruits of the temperate and torrid zones are easily grown; but little attention is paid to agriculture. Vast numbers of cattle, and to a less extent horses, mules, goats, and sheep, are reared.
The chief towns are Ciudad Victoria, the capital, Mata-moros, and Tampico.