Cindy, the Nathaniel F. SEGERS I have appears to be a close match to yours, but there are some discrepancies in dates.
My Nathaniel F. Segers was born 16 Feb 1841 (according to his Railroad Retirement Board record, citing an entry in the Segers family bible).He married Harriet A. HOWARD, who according to the 1900 census was born May 1842 in New York.I have them living in Rock County Wisconsin in 1870, with two daughters--LAURA (age 5) and MATTIE E. (age 3).This would put their probable marriage date sometime before 1865.
Nathaniel and Harriet had two other children--SUSAN BELINDA b. 10 Nov 1876 in Magnolia, Rock Co. Wisconsin, and a fourth child who likely died young.
SUSAN B. SEGERS married my great-uncle WILLIAM EDWIN SMITH in May 1904 in Janesville, WI. They had one daughter, MARION ALICE, born in 1908.
I have additional information on Nathaniel/Harriet and on Susan B. and her sisters that I would be happy to share if you think this is one of your collateral SEGERS lines.