.  [Index to] Early Marriages in Livingston County, Michigan, 1836-1933 (online at the Livingston County MIGenWeb site; compiled by Dianne Richards). I have extracted only the marriages in the 1800s and placed them in chronological order:

Bride or Groom	Spouse	Vol	Pg	Year
HOPKINS, Selinda	Selah B. FITCH	1	75	1840
HOPKINS, Mary	Elias J. SMITH	1	96	1841
HOPKINS, Caroline	Alexander PARKER	1	116	1842
HOPKINS, Loren	Jerusha C. DUNN	2	103	1853
HOPKINS, James	Hellen BARRACK	3a	3	1867
HOPKINS, Charles E.	Armintha WELLER	3a	12	1868
HOPKINS, Hannah A.	John B. SMITH	3a	64	1874
HOPKINS, J.A.	Nellie J. PERRY	3a	164	1883
HOPKINS, Sarah L.	Wm. B. MARSHALL	4	30	1890

See Portrait and Biographical Album of Ingham & Livingston Counties, Michigan for a biographical sketch of William B. MARSHALL's father.
(http://www.memoriallibrary.com/MI/LivIngPB/bios477-484.htm#478)

.  Jack & Marianne Dibean.  Index to Dibean's Michigan Marriage Collection (online at the Michigan Family History Network; note that this is a secondary source of user-submitted marriages, not extracted primary records, so caveat emptor):

Alexander McIntyre PARKER	Caroline HOPKINS	18 Apr 1842	Livingston Co.
Philander HOPKINS	Emeline EGGLESTON	Abt 1863	Livingston Co.
Samuel Lucas HOPKINS	Philancy HOLT	Abt 1837	Livingston Co.
August F KAISER	Alice May HOPKINS	09 Oct 1882	Macomb Co.
Charles HOPKINS	Cynthia Ann ADAMS	16 Feb 1859	Macomb
Ebenezer M BIRD	Cynthia C HOPKINS	23 Dec 1884	Berrien

many other HOPKINS marriages in the database

.  Livingston County Clerk.  Livingston County, Michigan, [Partial] Death Index, 1867-1948 (online at the Livingston County MIGenWeb site; extracted from LDS microfilm by Dianne Richards — the index is not complete for the period covered):

Last Name	First Name	Vol	Page
HOPKINS	Jenny H. Gage	2	237
HOPKINS	Joseph	1	212
HOPKINS	Robert	2	338
HOPKINS	William Joseph	4	115
HOPKINS	Wm.	2	38

.  Samuel W. Durant.  1880.  History of Ingham and Eaton Counties, Michigan.  D.W. Ensign & Co., Philadelphia (excerpts online at the Ingham County MIGenWeb site).

Alaiedon Township Land Entries
Section	Name	Date
5	Samuel HOPKINS	13 Dec 1836
6	Samuel HOPKINS	1 Nov 1836

.  U.S. Dept. of the Interior, Bureau of Land Management. The Official Land Patent Records Office.

Date	Certificate No.	Land Office	Patented By	Acres	Location	State	County*
2 Nov 1837	694	Ionia	Samuel Hopkins of Tompkins County, New York	296.48	E S6.T3N.R1W	MI	Ingham
2 Nov 1837	1654	Ionia	Samuel Hopkins of Tompkins County, New York	47.1	N½ NW¼ S5.T3N.R1W	MI	Ingham
1 Jul 1861	8451	East  Saginaw	Samuel L. Hopkins of Gratiot County, Michigan	200	SW¼ NE¼ S14.T13N.R2W  E½ NW¼ S14.T13N.R2W  N½ SE¼ S14.T13N.R2W	MI	Midland
*The county is not given on the original certificate, which describes the location of the land solely in terms of Aliquot, Section, Township, and Range.  The county names must have been added to the database at some later time, probably when the certificate data were computerized.