Some people, it seems, live near the borders, whether it county lines, state's or even countries. Knowing that helps you in your research! Recommendations are that you should search for local maps and gazetteers. What are gazetteers you say. Accordingly to Wikipedia, a gazetteer is a geographical dictionary or directory used in conjunction with a map or atlas. It typically contains information concerning the geographical makeup, social statistics and physical features of a country, region, or continent.
Sometimes you may be lucky to find maps or gazetteers online. With Google you have tab mark Map to check, but with other search engines, you may have to type the name of the community, county, state or country in quotation marks, along with subject "map" or "Gazetteers" to see if there is one online or if there is a printed copy nearby.
Check, also, the history of the community, county or state to see if the boundaries have changed or whether there was a name changed. Counties can be split or be carve out of another, cities or communities can have name changes or be incorporated into another larger community.
With printed maps not all communities are shown! There’s only so much room on most printed maps. Google Maps, with it features of zoom will allow more information to be seen, but this is with modern information.