by Robin Tuck
Driving down the highway, I often pass a green sign indicating I have just crossed the border into a new county. Normally, there are no hints anywhere suggesting that I might not have entered the county at an angle, so I take it for granted that the land on both sides of the road are now in the new county.
Restating this, I am traveling down a highway in county "A" with the lands on both sides of the highway being in county "A", then, all at once, I pass a sign telling me I have entered into county "B" with the lands on both sides of the highway in county "B".
Often I look for a fence line stretching off into the distance to indicate a property border coinciding with the county line to see if it is indeed perpendicular to the highway. Sometimes the fences are there, but most often they are not, causing me to not really know the exact layout of the highway and the county line.
Most of the time it doesn't matter where the county line truly is or at what angle I have crossed it because I quickly pass the line and am sufficiently 'inside' the county that any bird I see is also in the county.
Every now and then, however, where the county line is exactly does become an issue. Consider the case where a county line or national border follows a river, such as is the case along the Rio Grande in Texas. In this case, the ABA rules are that the bird wasn't seen in the United States unless it was in United States territory or airspace.
When we are close to a border we need to pay close attention to where the bird is when we see it in order to appropriately record where it was seen. This is perhaps both good and bad. If the bird fly's from one side to the other we can record having seen it in both places, but if it doesn't fly into the place we want while we are watching, we cannot count having seen it at that place.
This problem would not normally justify a lot of concern except for the county contest going on this year (2000) and the Williamson's Sapsucker nesting along the Provo River upstream from Provo Falls. As it turns out, examining common maps to find which county the Sapsucker is in yields confusion. The Utah Atlas and Gazetteer published by Delorme (all editions) show the border between Wasatch and Summit Counties following the Provo River until the spot where Provo Falls ought to be, then heading toward the ridge line. Provo Falls is not marked on the map causing the confusion. Referring to other maps did not resolve the issue until I obtained the 7.5 Minute Quadrangle map for Mirror Lake. This map has sufficient detail to show Provo Falls and the parking lot overlooking it, and it shows the county line continuing to follow the Provo River well past the place where the Williamson's sapsucker was nesting. This means that the Sapsucker nest is in Wasatch County.
Another conclusion that can be drawn from this is that all maps are not created equal. In this case the Delorme map is clearly wrong about the county line. In fact, the Delorme maps available on computer are equally wrong showing that the same data is used for both the print and computer versions, a fact that is not surprising. Of course, this does not mean that the USGS 7.5 minute map is absolutely correct, but that we place a higher degree of confidence on it than on commercial maps.
My conclusion: When resolving questions about locations and boundaries and positions of geologic features, consult the highest resolution official maps available.