When Was American Currency Invented?

In 1690 colonies began issuing paper money which was based on foreign currencies. In 1775 the US created what was called the continental currency, but that currency failed because it was backed only by the anticipation of tax revenue and because it could be easily counterfeited. In 1785 the dollar was created and became the official currency of the US, but no coins were created until 1793 and no "true" bills were created until 1861. So to answer your question the first true american currency was created in 1775, but the american currency as we know it today wasn't created until 1785.

On March 10, 1862 the first United States paper money was issued. The denominations were $5, $10, and $20. They became legal tender by Act of March 17, 1862

I believe that may be the answer you were looking for.

Paper currency and coin currency were developed in Asia, Europe and Africa so "invention" is not an appropriate term for their usage in the Americas. "The Americas" are the continents of North America and South America.

Do you wish to know when paper money was first printed and metal coinage first minted in the United States of America? Or in the areas that later became USA? Or in the Americas?

The Spanish were probably the first to mint coins in the Americas. A coin might be divided into 8ths ... A usage with survives in the English language in references to a 25-cents as "two bits" and "8 bits: A dollar".

The "penny" was a coin in some areas, but it was superceded by the "one cent" piece when the colonies unified as the United States of America. The "decimal" coinage (instead of l.s.d. For pounds-shillings-pence ... Another tale in how l = pound and d = pence) may be an 18th-century USA invention.