Under Mexican jurisdiction, Hispanic families began moving into the area during the early to mid-19th century as part of land grants to help the Mexican government fill and occupy the territory. However, large-scale settlements were difficult to establish because the Utes were weary and very hostile towards Euro-American settlement, and would chase off many people who attempted to do so. The most successful early settlement nearby was called 'La Loma', established a few miles east of where the current town site is today. This area was chosen because there was a particular section of the Rio Grande here where it could be crossed safely and easily – one of few known for miles during this time. After the Treaty of Guadalupe-Hidalgo was signed in 1848, jurisdiction of the land in and around Del Norte transferred from Mexico to the United States, but settlement by Americans in the area was delayed by civil strife (including the American Civil War) throughout the 1850s and 1860s. Most American settlements began in the area around the early 1870s, by prospectors searching the nearby mountains for minerals, such as gold and silver, particularly near an eventual boom-town named Summitville, located at the base of South Mountain near Bennett Peak.