King George III, CT/Vermont Colonial??

Back.

Too hard to call from the pic.

Could be quite a few different coins...if it was a KGIII it would most likely be a period counterfeit as KGIII did not allow coins any longer to be legally brought to the colonies and that was due to extensive counterfeits.

Could be a State coin like Vermont etc.

Best thing to do is measure its diameter and weight in grams. Then go to https://coins.nd.edu/ColCoin/ and look up counterfeit KGIII's as well as state coins with a bust facing right and a seated Britannia on the obverse.
Note the diameters and weights....then compare what you have. Even with corrosion the coin will not 'shrink"....it will weigh close to what it was 200+ years ago..maybe a tad less but not way off I would not think.
Usually the thin KG style coppers are counterfeits as they seriously under weighted them sometimes by 25%.
I would think a Vermont coppers weight would be originally much more than a KGIII colonial era counterfeit. A VT copper weighs around 7.7 grams whereas some of the counterfeit KGIII's would be 6.6 grams and less.
It could also be a Machin Mills which is also a type of counterfeit but they were pretty close in weight and I have found a few and they are a great find.
Anyway without seeing any writing around the head it can be hard to nail it down
Scott

Old historic relic, or Chuck-e-cheese token?
Precise diameter, mass, and side-lit photos(shading, or whatever shows the detail best) I see some partial lettering or numbering. try to id that a little better.

Could be a George I halfpenny.

Voriax