This letter was sent from Camp #17, "Banks of the Humboldt River," and it described, to his father, his trip with Mr. Parker (an Indian agent) and Mr. O'Sullivan (the U.S.G.S. photographer) to Pyramid Lake, Nevada. Part of this letter is missing

This letter was sent from "Camp #19 Buena Vista" and discussed his summer's field work. Of particular interest in this letter was a list of Piute Indian names for birds and simple expressions that Ridgway has put together

This letter was sent from "Headquarters U.S. Geological Exploration 40th Parallel", Carson City, Nevada and detailed photographs that he had sent home with the letter. These photographs were not in this collection

postmarked the Great Salt Lake City, Utah. Part of this letter is missing, but the existing piece discussed survey events, and it mentions some of the party members. This letter was likely mailed during the middle of the summer of 1868

This letter was sent from the Smithsonian institution and was his first letter written home after returning to the east. The letter described his three day trip on the Union Pacific Railroad back to Washington, D.C. It also mentioned a discovery that he had made on western hawks

This letter was sent from the Smithsonian Institution and it discussed specimen collecting that was done the previous year on the survey

This letter was sent from the Smithsonian Institution. It discussed the report that he was compiling from his survey work and a book that he was currently preparing about North American raptors

This letter was sent form the Smithsonian Institution . It told his father about Clarence King's decision to drop zoology and botany from the next year's expedition. Ridgway had been offered a trip to the west, anyway, but the only compensation would be to have his expenses paid

This letter was sent from the U.S.G.S. headquarters, Salt Lake City, Utah. It mentioned family matters, Granville Turner, and Spencer Baird

This letter was sent from the Smithsonian institution and mentioned his completed manuscript compiled from his survey trip. He went onto tell his mother that he was currently helping Baird on the "Manual of the Birds of North America."