The following biographical information from Grolier's Multimedia Encyclopedia:
The landscape painter Albert Bierstadt was the first artist of distinction to take as his subject the vastness of the mountains of western North America. Born in Germany, Bierstadt emigrated to the United States with his parents in 1832. After his early works were exhibited in Boston, he traveled (1853) to Germany to study painting for three years at the Dusseldorf Akademie. In 1857 he returned to the United States and painted throughout the northeast; in 1858 he made the first of several trips to the West. From sketches and oil studies done from nature (admirable works in themselves), he painted in his New York studio the huge, carefully detailed panoramic views of Western scenery that made him one of America's most admired painters in the 1860s and '70s. His approach to landscape was a romantic one, emphasizing and sometimes exaggerating the spectacular landforms and atmospheric effects he had seen on his travels, as in his dramatic The Rocky Mountains (1863; Metropolitan Museum, New York).
Bierstadt joined a surveying expedition to the western United States in 1858 after studying painting in Germany. The impressions and sketches made on this trip were the basis of many of his paintings.