This collection contains letters written by Captain Adna G. Clarke of Company H of the 20th Kansas Volunteers to his wife and other family members while serving in the Spanish-American War in the Philippines. Also in the collection are some ephemera from Clarke's time in the war and some news articles by and about Clarke from later in his life after he moved to Hawaii.

The Jane Comstock Clarke collection consists of a Clarke family photo album and loose family photographs, along with a few cards sent by Clarke and some news clippings from Honolulu, Hawaii newspapers about the poetry that Clarke published there using the pen name Jane Comstock.