I didn't see a response to my initial questions, but from what you mentioned, I suspect that there is a "subset" (or "region") of maps installed on your device. This often happens when you update the maps, and do NOT have enough memory in the device to hold the entire US states.
This can be checked by finding and looking at your "Map Info" screen, and seeing if there is a couple of letters AT THE END of the map file name, such as SE (for South-East), NE (North-East), etc.
The solution to this is to either:
1) update your maps and select a region that includes Washington state, OR
2) purchase and install a 4GB or 8GB microSD card, and then update your maps again - and this time installing ALL of the US maps. This will eliminate this type of issue in the future.
If you choose to get a microSD card, they should be available at most electronics, computer, or office supply stores and the like. If you need a reference to what you will be looking for, I have a link to the Amazon search results for an 8GB microSD card below.
8GB microSD card SEARCH
I hope this helps explain what I believe is happening. Please let me know your results or if you have any more questions.
Take Care & Travel Safe, Greg A.