History of northern Wisconsin: containing an account of its settlement, growth, development, and resources, an extensive sketch of its counties, cities, towns and villages, their improvements, industries, manufactories, biographical sketches, portraits of prominent men and early settlers, views of county seats, etc. Chicago: Western Historical Co., 1881. p.1187

Theodore Neilsen, Winneconne, dealer in dry goods, groceries and general assortment found in a country store; located in Winneconne in fall of 1850, and engaged in working in the lumber business and different kinds of employment until 1863, when he began in Butte des Morts in mercantile trade, where he remained three years and moved to Winneconne. He was born in Norway June 14, 1826; emigrated to America in fall of 1850. Married in Winneconne, Nov. 7, 1863, to Miss Lydia Pritchet, who was born in Delaware Oct. 13, 1844. They have two sons- Frank and Eddie. Mr. Neilson served as Postmaster in Butte des Morts, also as Town Treasurer and several other offices.