When I search for “Prince George’s County, MD” using the search toolbar, it shows up in the dropdown menu, but the result on the map is “bounding box” that encloses most of the county, but also parts of DC, Virginia, and other MD counties.
you can also search for this place directly by using the Place filter under “More Filters” in the Filters menu in the Explore page. that’s the way i usually filter for places. the location box, to me, is more of a secondary option if the place can’t be found in the place filter (because it doesn’t exist in iNaturalist).
in this particular case, i’m guessing the apostrophe in this place name is probably preventing the location search from being able to pick up the proper iNaturalist place. so it defaults to a bounding around the Google-defined place instead. (i suppose it’s a bug, but it’s such an uncommon case, and it has a workaround. so it seems to me like this may be best deferred as something to be addressed when the Explore page is revamped (https://forum.inaturalist.org/t/ideas-for-a-revamped-explore-observations-search-page/8439).