Is this the one that was up for eBay auction last week in Maine?
If so, wrote about it on my paddle blog recently. I've documented other substantially large (6 1/2 foot + paddles over the years, all sourced from Maine). The
post has links to those other examples if anyone is interested. It would be great if you could let us know the weight of your paddle.
Looks like you sanded off the weathered dull-grey patina to reveal the aged wood underneath. Extra long paddles like this were traditionally made from spruce. An 8ft paddle made from a hardwood would be quite heavy/cumbersome. Softwood paddles also tended to have thicker shafts for strength and yours looks to have much thicker shaft than a proportional hardwood paddle would need. Weighing your paddle would help to confirm. Spruce was and still is a standard wood for making one-piece rowing oars for the same weight issues.
The Wabanaki peoples of East Coast utilized long paddles for standing and paddling their canoes.
The original seller referenced the paddle could be Penobscot or Passamaquoddy origin. It certainly has the carved shape common to their tribal tradition. However, extra long paddles like this , especially those over 7ft, were also commonly used by lumbermen standing up and steering wooden bateau craft during log drives.
The neatly engraved/branded letters near the throat look quite "professionally" done rather than hand carved. The seller's original post mentioned these letters (possibly O P CO or O B CO) appear on both sides of the blade. They might refer to a specific Maine logging company and quite probably your paddle was once "company equipment". During these log drives there would have been multiple companies using the river systems to get their branded logs to their respective mills.
Hope you get much enjoyment out of it. Would be great to see this bit of restored history in action so feel free to post some pics next time you get out.