Except in Cook County, all Illinois marriage certificates since 1877 have a Board of Health form attached that asks for the town of birth, the full names of the parents, and if this is a first marriage.
Research tip: The 1900 and 1910 censuses asked how many years a couple had been married. While not always perfectly accurate, this should get you into the right range of years to search when you're looking through the indexes.
- Boone County Marriage Indexes for 1839 through 1923 are at the Belvidere Library, the Family History Center, and the Rockford Public Library. Marriages mentioned in the Belvidere newspaper between 1851 and 1899 are listed in a typewritten book that Helen Maxwell Williams prepared. (Available at the Belvidere Public Library)
- Winnebago County Marriage Index, through 1916, is at the Belvidere and Rockford Public Libraries as well as the Family History Center. For marriages after 1877, it gives dates and ages and the full names of spouses. Also included are bride and groom indexes. Actual records are now available at the Rockford Public Library on microfilm.
- Indexes for both Winnebago and Boone Counties may be purchased at Ancestor Publishers on microfiche.