The Personal Correspondence series is the most voluminous series and is subdivided into correspondence to C.P. Dorset, Nannie Dorset, Nannie Colwell, Marian Dorset, Helen and Bernard Dorset, and Malinda Hammer. Letters to each person are grouped by immediate family, extended family and friends. For example, letters to Nannie Colwell first include those from her parents and siblings, then those from aunts, uncles, and cousins from the Colwell, Dorset, and Hammer families, and finally the many letters from friends around the world. Some of the more interesting letters to Nannie are those from Alice Seymour MacHaffie, who lived most of her life in China. There are also letters to her mother, grandmother and aunt in La Crosse, which are very illustrative of the social life in La Crosse in the late 1900’s. The earliest letter is from 1850; they continue until 1965.

The letters to C.P. Dorset are a small group of letters from Nannie Colwell and a few from other friends. The letters to Nannie Dorset are mostly from her children when they were away from home - at school or traveling. Nannie Colwell’s letters from Europe and China are most interesting. Helen’s letters have some very detailed accounts of university life. Letters from Nannie’s husband, Rev. Dorset, are very lively and informative about the life of a teacher and clergyman in Wisconsin and Texas. The letters to Marian Dorset are mainly from her father and her gentlemen friends, and include some pleasant love letters. In addition to the letters from her family, Helen Dorset’s letters are from her wide circle of friends and illustrate her many interests in life. Letters to Bernard contain a few from his father; the rest are from friends. The letters to Malinda Hammer are from her family and one distant cousin. The letters vary a lot in quality and interest. They are usually very formal in tone, as was the time period. At times however, the writer breaks through - some letters are very illuminating about the writer’s personality and attitudes.