The Old River connects Deepwater Slough with Boom Slough in the Skagit River Delta. It is both adjacent to and within the Skagit Bay Estuary Wildlife Area Unit on Fir Island. As with most of the sloughs in the delta, a boat is required for access.
A quick note on font size: you have to make your text editor font quite large to make it legible for your viewers! It will take a little while to get used to this. I use 26-point font in my editor, which provides only about 30 visible horizontal lines of code.