The last purchase that defined the border with Mexico was made in 1853 west of the Rio Grande and south of the Gila River and is known as the Gadsden Purchase. That will not be the end of the story since rivers do change their course from time to time and the courts are required to decide the case. Geographic irregularities include:
Gadsden Purchase
The Treaty of Guadalupe Hidalgo and the Gadsden Purchase...the actual borders of each state had been established at different times later on....but those 2 treaties established the national borders.
Alaska and Hawaii. Alaska borders Canada. Hawaii is a group of islands located in the Pacific.
Maine
Technically, Canada as it borders Alaska to the east. However, the Atlantic Ocean is to the east of the Contiguous US (Lower 48).
Technically, Canada as it borders Alaska to the east. However, the Atlantic Ocean is to the east of the Contiguous US (Lower 48).
(1853) U.S. purchase of land from Mexico that included the southern parts of present-day Arizona and New Mexico; set the current borders of the contiguous United States (the U.S. states, minus Hawaii, Alaska, and commonwealth of Puerto Rico)
They are Alaska, Washington, Oregon and California.(Alaska is continental, but it is not contiguous with the "lower 48.")
Contiguous means that their borders are touching the continental US. Alaska and Hawaii do not touch the mainland.
Congress established the lower federal courts
Lower mantle
The only Canadian province which borders Michigan is Ontario.
The fact that Canada borders on the United States means that shipping costs are lower than from other countries. Also, the US dollar is usually stronger than the Canadian dollar meaning that goods can be bought by Americans at effectively lower prices in Canada than in the United States.