The geography of Texas covers a wide and far reaching scope. Occupying about 7% of the total water and land area of the United States, it is the second largest state after Alaska, and is the southernmost part of the Great Plains, which ends in the south against the folded Sierra Madre Oriental of Mexico. Texas is in the south-central part of the United States of America, and is considered to form part of the U.S. South and also part of the U.S. Southwest.
The Rio Grande, Red River and Sabine River all provide natural state lines where Texas borders Oklahoma on the north, Louisiana and Arkansas on the east, and New Mexico and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south. Austin, the state capital is farther south than all other US state capitals except Honolulu.
By residents, the state is generally divided into North Texas, East Texas, Central Texas, South Texas, and West Texas, but according to the Texas Almanac, Texas has four major physical regions: Gulf Coastal Plains, Interior Lowlands, Great Plains, and Basin and Range Province.