Mesilla (also known as La Mesilla and Old Mesilla) is a town in Doña Ana County, New Mexico, United States. The population was 2,180 at the 2000 census. It is part of the Las Cruces Metropolitan Statistical Area.
The village of Mesilla was incorporated in 1848, after the Treaty of Guadalupe Hidalgo moved the U.S.-Mexico border south of the village of Doña Ana, placing it in the United States. A small group of citizens, unhappy at being part of the United States, decided to move south of the border. They settled in Mesilla at this time. By 1850, Mesilla was an established colony. By this time, its people were under constant threat of attack from the Apache. By 1851, the attacks caused the United States to take action to protect its people just to the north of the border, in the Mesilla Valley. They did this by creating Fort Fillmore. As a result of the fort, the United States declared the Mesilla Valley region part of the United States. Mexico also claimed this strip of land, causing it to become known as "No Mans Land." This boundary dispute, which was officially caused by a map error, was resolved in 1853, with the Gadsden Purchase. Mesilla became a part of the United States, as well as the southern part of New Mexico and Arizona.
Two battles were fought at or in the town during the Civil War. Mesilla served as the capital of the Confederate Territory of Arizona in 1861-1862 and was known as the "hub", or main city for the entire region. Recaptured by the Volunteers of the California Column, it then became the headquarters of the Military District of Arizona until 1864.
During the "Wild West" era, Mesilla was known for its cantinas and festivals. The area attracted such figures as Billy the Kid, Pat Garrett and Pancho Villa. The village was also the crossroads of two major stagecoach lines, Butterfield Stagecoach and the Santa Fe Trail. The village of Mesilla was the most important city of the region until 1881.
In 1881, the Santa Fe Railway was ready to build through the Gadsden Purchase region of the country. Mesilla was naturally seen as the city the railroad would run through. However, the people of Mesilla asked for too much money for the land rights, and a land owner in nearby Las Cruces, New Mexico, a much smaller village than Mesilla, stepped in and offered free land. The city of Mesilla has not grown much since, and Las Cruces has grown to a population of an estimated 95,000 people (2010) and is currently the second largest city in New Mexico.