AFAIK only locks got built, never any actual canal like the C&O. The Patowmack/Potomac company ran into engineering problems to the west that were beyond their financial resources.
When the Erie opened up in New York it siphoned off a lot of the westbound traffic that the Patowmack company had hoped to get. IIRC the C&O took over the remains of the company, and then railroads began putting canals out of business.
Another bit of canal trivia since you seem to enjoy it like I do- the Watergate neighborhood down in Georgetown/DC took its name from an actual “water gate” on the C&O down where Rock Creek empties into the Potomac. Has something to do with a “tide lock” but I’m not sure how it works. I think the water gate or its ruins still exist.
https://en.m.wikipedia.org/wiki/Patowmack_Canal
Been on the Georgetown locks of the C&O (never mind elsewhere). The whole thing is very cool. I just love history and old stuff.