Possible Marriage Record 29 Mar 1883 in Manitowoc County.

1900 US Census, 12 Jun 1900 p43/57
Krahn, Frank, b. Jan 1860 in Germany, parents born in Germany, age 40, occupation, engineer, married 17 years.
Mary, wife, b. Nov 1864, born in Wisconsin, parents born in Germany
Joseph, son, b. Dec 1883, born in Wisconsin, “
Leon, dau, b. Dec 1885, born in Wisconsin, “
George, son, b. Feb 1888, born in Wisconsin, “

1905 Wisconsin Census, city of Kaukauna, Outagamie county:
Krahn, Frank C, age 45 born in Germany, parents born in Germany, locomotive engineer
Mary, age 41, born in Wisconsin, parents born in Germany
Joe, age 21, born in Wisconsin, bookkeeper
Leona, age 18, born in Wisconsin, teacher

1910 US Census, 23 April 1910, Kaukauna, Outagamie county:
Krahn, Frank, age 50, married 27 years, born in Germany, parents born in Germany, locomotive engineer
Mary, age 46, born in Wisconsin, parents born in Germany, mother of 4 children, 3 living
Joe, age 26, born in Wisconsin, bookkeeper
George, age 22, born in Wisconsin
Miller, Barbara, age 69, widow, born in Germany, parents born in Germany, 6 children, 4 living

1920 US Census, 14 Jan 1920 p32/33
Krahn, Frank C, age 60, immigrated 1865
Mary, age 56, wife, born in Wisconsin, parents born in Germany
Krahn, Fredrika, age 89, mother, born in Germany to German parents, immigrated in 1865.

1936 and 1938 Kaukauna City Directory:
Krahn, Frank C (Mary T) h103 E 4th