Reddit reviews Bird Feathers: A Guide to North American Species

Eh, can't sleep. (drags out feather reference book)

I'd say you most likely have a leading primary from a Herring gull. Ref. pic. Looks like the white wing tip and leading edge have been worn away by use.

Fun fact: pigment makes feathers/scales/skin physically stronger - white areas wear away quicker under use. This is part of the reason why mostly-white birds like gulls tend to have dark coloring along the leading edges of their flight feathers.