I'll throw a little fuel on this fire. I think the "DEP'S LISTS OF STREAMS SUBJECT TO
THE SUBMERGED LANDS LICENSE PROGRAM" sums it up perfectly . . . the definitive answer to your question is a solid "maybe."
According to this document (marked DRAFT by the way) "Tobyhanna creek, in the county of Monroe, from the river Lehigh to the junction of the Tunkhanna" was historically declared a "public highway" and therefore used for commerce since April 16, 1838. The Pennsylvania Department of Environmental Protection (DEP) leverages that designation as evidence of Commonwealth ownership of the submerged stream beds under the Dam Safety and Encroachments Act.
Before the OP drops a few hearts on this post, the document's introduction states plainly that the table of waterways contained within it are not a final legal determination of whether a stream is navigable under federal or state law. So, like
@afishinado already said, in Pennsylvania, a definitive legal declaration of navigability can only be made by a court.
You're not going to get a more solid, unambiguous, crystal clear "Maybe" from any other published source IMO.
I guess if I wanted to start legal proceedings to turn a maybe into a definitely (one way or the other), I'd first be looking here to see if the stream in question was listed and decide my next steps from there.
It probably wouldn't be walking in with a rod strung up quite yet but you may be able to float down it in a canoe
🙂