The only parts of the continental USA with land antipodes are a small patch in Montana, opposite Kerguelen Island (which also straddles the border into Canada), and two small patches of Colorado which are opposite the remote Île Amsterdam and Île Saint-Paul. Parts of the far north of Canada and Alaska, and most of Greenland, are antipodal to the coast of Antarctica.
The only parts of Europe with land antipodes are the parts of Spain and Portugal opposite New Zealand (which also grazes Morocco), and Svalbard, which has antipodes in Antarctica.
Africa contains the antipodes of a number of Pacific islands: Hawai'i, and everything from French Polynesia to Vanuatu and New Caledonia.
South America contains the antipodes of parts of eastern Asia: most of eastern China (with Mongolia mapping onto the tip of Argentina and Chile), Taiwan, sothern Vietnam, Cambodia, the Philippines, Malaysia, Brunei, and most of Indonesia.
It's not much, is it?