NELSON/NELSEN Denmark to IL to CO

Lars Nelson/Nelsen was born in April 1832 in Denmark. He emigrated from Denmark via Chicago, Cook, IL to Park County, CO. He was naturalized in 1872. He married Susanna/Susan G. ? and they had 4 children as follows:

Albert N. born 25 Mar 1865, Chicago, Cook, IL
Anton, born 13 Dec 1866, Chicago, Cook, IL
Julius, born 13 Dec 1866, Chicago, Cook, IL
Fred W., born 1868, Chicago, Cook, IL

This family was connected to Thomas ERICKSON of Omaha, NE, who also emigrated from Norway to Chicago and to Omaha.

Would like to hear from anyone who might have information on any of these families. Thanks!