Keep this open while it saves. iOS pauses downloads when you switch apps or the screen locks, which looks like it has stalled. Parcels and the overview land first, so the map is usable early; close-zoom detail is the slow part and comes last.
GPS works without signal, so once saved you can stand on the property and see your position against the boundaries. Add this to your home screen to keep the saved map from being cleared.
Open location in
Directions to here
Tap anywhere on the map to drop a point. Works offline; the map apps need signal.
Tap the map to add points. Three or more points enclose an area.
Querying Washington County GIS