The collection contains a transcript of a diary kept by Andrew Hall Gilmore (transcribed by Raymond M. Gilmore). The diary provides an account of the overland journey taken by Gilmore from Indiana to California. The diary begins in Indiana on March 12, 1850 and ends in California on January 1, 1853. Throughout the diary, Gilmore describes his surroundings, including wild life, land use, camp life, towns he travels through, relations with the Indians, etc. The collection includes several letters dating from 1851-1852 written by Gilmore from Placerville, California to his brother James. The letters describe various aspects of gold mining including the building of canals and flumes.