The state of Texas shares its southern border with Mexico.
Oklahoma shares most of Texas's northern border.
Texas is a state of the United States of America. It is not itself a country, and there is no country within the state. There is a country that shares a border with Texas, and that related question is linked below.
Too many to name them all, twelve in the US north and four in the south.
The Country that shares the southern Border with the US is Canada.
Venezuala shares a border with Brazil.
Mexico.
Country that shares myanmar's southern border?
Slovenia shares the largest border with Italy.
Portugal shares Spain's western border.
Israel shares a border with Egypt which is in Africa.
Nevada, Arizona and Oregon.