I've found my 3rd great-grandfather's sister living with her son and his family in Denver, Arapahoe County, Colorado, in the 1880 census.
L. U. Albers is listed as a merchant in the image shown here which is a partial copy from the 1880 Census (page 157A of Enumeration District 7). The family had only lived in Colorado a few years as all the children, including the youngest who was two years old, were listed as being born in Illinois.
Antje Albers, shown in the second image, is listed as L. U.'s 69 year old mother. Antje's maiden name was Antje Ehmen, born in 1811 in Wrisse, Ostfriesland, Germany. Her brother Johann Goldenstein (1814-1891) was my third great-grandfather. He remained in Wrisse and did not emigrate.
Historykat has released the 1885 census for Colorado and my next goal is to try and find her in that record.