Brand-new TreasureNet member Kasone asked in his very first post at T-Net:
>
Anyone know anything about this? new to detecting.
Your find appears to be what collectors of Historical Buttons call a brass 1-piece "flatbutton." It appears to have a backmark (maker's/dealer's mark) stamped into its back. If the marking is written in raised lettering, your brass flatbutton dates from around 1790 into the 1830s. If the lettering is indented, it dates from about 1810 into the 1830s. In the mid-1830s, these plain 1-piece flatbuttons rapidly fell out of favor with the public due to the advent of mass-produced inexpensive 2-piece (hollow) brass buttons with an ornate emblem instead of a plain front.
Here's additional info for you, since it seems you are new enough at the relic-digging hobby to not yet know the "specific" ID of your find. (I do this because 40-something years ago when I was new to relic-digging, a couple of kindhearted Oldtimer diggers very generously taught me a lot of their knowledge, for free.)
The great majority of brass 1-piece flatbuttons found in the US were actually made in Britain and imported here, because until the mid-1820s the young US button-making industry was incapable of mass-producing enough metal buttons to supply the demand from the Clothing Industry. Backmarks on British-made flatbuttons often (but not always) have clues which reveal their national origin... such as the British spelling of the word color as colour, or a British Royal Crown marking, or even the word London.
Welcome to T-Net, and in particular, to its "What Is It?" forum, the best place on the internet to get unknown objects CORRECTLY identified.