Dukes County is set to receive more than $3.3 million in federal coronavirus relief funding — a hefty windfall nearly the double size of the county’s annual budget. The money is part of the Biden administration’s $1.9 trillion American Rescue Plan, intended to combat the coronavirus pandemic, including public health and economic impacts. Although much of the federal money will go directly to municipalities and states, more than $65 billion in aid has been allocated to county governments around the country. A total of $400 million has been allocated the six vestigial counties in Massachusetts: Barnstable, Bristol, Dukes, Nantucket, Norfolk, and Plymouth. The other eight state counties were abolished long ago, with cities and towns set to receive larger allocations of federal aid in lieu of the county funds.