who designed it?
James B Longacre.
Three-cent nickel
The copper-nickel three-cent piece, often called a three-cent nickel piece or three-cent nickel, was designed by US Mint Chief Engraver James B. Longacre
where was the three-cent nickel minted? United States Bureau of the Mint.
wiki:19329226
Three-cent nickel [SEP] Introduction
The copper-nickel three-cent piece, often called a three-cent nickel piece or three-cent nickel, was designed by US Mint Chief Engraver James B. Longacre and struck by the United States Bureau of the Mint from 1865 to 1889. It was initially popular, but its place in commerce was supplanted by the five-cent piece, or nickel. With precious metal federal coinage hoarded during the economic turmoil of the American Civil War, including the silver three-cent piece, and even the copper-nickel cent commanding a premium, Congress issued paper money in denominations as small as three cents to replace the hoarded coins in commerce.