I'm leaning more toward Acer saccharum - Sugar Maple.
Sailtheseas could help us by saying where (zone, city, state, country?) s/he is from, and where the specimen is collected from.
If you know what plant this leaf is from, show more of it as well. Form, branching, buds, twigs, bark all assist in identification. Leaves aren't always needed, and are even unnecessary.
I would still suggest A. platanoides, because although lobes are long acuminate in A. saccharum, they are never sharp spinose as we can see here and typical of A. platanoides. Perhaps underview of leaf would confirm it further: bright green and lustrous in A. platanoides and lighter green in A. saccharum
I would rather see the twigs, buds, and/or whole tree. No amount of variable leaf morphology will change the dormant buds' characters.
Acer saccharum has narrow sharp pointed brown buds.
Acer platanoides has plump rounded greenish/purplish buds.
Thanks everyone! I have to go back to that area on Friday so I will get more picks then. Still learning! :)