An online tree indicates that an aunt of mine was married in Cincinnati, Hamilton County, Ohio, in 1869. The only source that tree has for this date are two other online trees. There is no additional information to indicate how the information was obtained–no minister or justice of the peace name, no church, address, etc. A search of extant Hamilton County marriage records did not locate the marriage.
The only way I know that my aunt married is because her husband’s name is listed when she inherits from her brother’s estate a few years later. That estate record is my evidence for the marriage and I’m using the date they are mentioned in the court record as a “married by” date.