- The vast and rugged terrain: The expedition traveled through some of the most difficult terrain in North America, including deserts, mountains, and rivers. This made it difficult to travel and transport supplies.
- The lack of water: The expedition often found itself in areas with little or no water. This made it difficult for the soldiers and animals to survive.
- The heat and cold: The expedition experienced extreme temperatures, from the hot desert sun to the cold mountain snow. This made it difficult for the soldiers to stay comfortable and healthy.
- The lack of food: The expedition often found itself in areas with little or no food. This made it difficult for the soldiers to stay nourished and strong.
- The hostility of the Native Americans: The expedition often encountered hostile Native American tribes. This made it difficult for the soldiers to travel and explore safely.
- The diseases: The expedition was also plagued by diseases such as smallpox and measles. These diseases killed many of the soldiers and weakened the rest.
- The desertion of soldiers: Many of the soldiers deserted the expedition due to the harsh conditions and lack of success. This made it difficult for Coronado to maintain a large enough force to continue the exploration.