The closest Spanish speaking countries to Spain are Andorra and Portugal. Andorra is a small country located between Spain and France, while Portugal shares a border with Spain on the western side of the Iberian Peninsula.
Mexico to United States.
Texas, New Mexico, Arizona, and California all share a border with Mexico, the only Spanish-speaking country that borders the US.
The only country sharing a border with Portugal, that is, Spain
The Spanish-speaking country that is furthest north is Mexico. Its northernmost point is at the border with the United States along the Rio Grande.
Colombia and Brazil border Venezuela.
Portugal, and France are countries that border Spain and do not speak Spanish. Spain also has international borders with the United Kingdom at Gibraltar, and with Morocco at the Spanish Autonomous Cities of Ceuta and Melilla in Africa. Neither Morocco nor the UK are Spanish speaking countries.
Mexico
Spain and Portugal. The legacy is that whole od the Americas , south of the USA/Mexico border is Spanish speaking, except for Brazil ,which is Portuguese speaking.
The only spanish speaking country that borders the United States is Mexico. For states sit along the border: California, Arizona, New Mexico, and Texas.
An English speaking country (United States) borders a Spanish speaking country (Mexico) in the southern region of the United States and the northern region of Mexico. Another example is Gibraltar, a British Overseas Territory, borders Spain.
California, Arizona, New Mexico, and Texas are the US states on the border with Mexico.