Which county was that?

A patron came in this week looking for marriage information from 1786 for Washington County, TN. She had researched enough to know Washington County, TN came out of Washington County, NC. The challenge was we needed to go back even farther in the history of this region to really find where she needed to look. Turns out Washington County, NC wasn't formed until 1799 which is after her ancestor's marriage. It came out of Tyrrell County which was formed in 1729. I found this information in the Red Book, which was discussed in a previous blog. After determing the right county name for the time frame we had to find where the records of marriages might be available for research. The Red Book gives me that information as well. The book ultimately directs her to the Index to Marriage Bonds Filed in the North Carolina State Archives, a microfiche which is available through the local Family History Center. Hopefully she'll find the marriage in the index and then can contact the North Carolina State Archives for a copy of the record itself. We could have wasted a lot of time looking in the wrong records and awaiting an interlibrary loan if we had not first researched the history of the county. In genealogy it's important to know you're looking in the right place before jumping in.
One other note, she had a copy of two pages from a book and did not know the source. It included a titled list. We were able to Google the title list and come up with the source which was an 1850 National Genealogical Register Quarterly which has been added to the Google Books collection. That too saved us a wait for an interlibrary loan. Digited Google Books can be a great help in research.