Caroline Eugenia Augusta Nylander was born in 1847 in Bryngeltorp, Sweden. She likely immigrated to Utah between 1863-1867, following the common route of taking a ship from Sweden to Liverpool, then New York, and traveling by river boat and train to Wyoming, Nebraska. After arriving in Utah, she married Henry Day in 1867 in a plural marriage in Salt Lake City. They had two children together before she passed away in 1871 in Draper, Utah at the age of 24.