I found the approximate bounardies with this Snohomish County PDF file (https://www.snoco.org/v1/services/Docs/SCD/PDF/PDS_UGA/MarysvilleUGA.pdf). I don't know the exact boundaries on the Internet as I don't exactly know where to look and I looked throughout the Internet and that is the closest thing to a boundary I can find. This Marysville Fire document has a legal boundary in Exhibit A but I do not know how to read that at all (https://www.marysvillefiredistrict.org/app/download/7097181904/Quil+Ceda+Village.pdf).