There is a box at the top of the results page which you can tick to get country specific results
It's a minor annoyance that I've got used to, and hasn't persuaded me to go back to Google (I've used DDG as first choice for probably a little over 5 years now).
If DDG can't deliver the goods, !b (bing) is second choice, !mill (Million Short) probably third, then as appropriate, a mix of !azuk (amazon UK), !w, !ox (oxford dictionary) and a mix of others including !g as last resort. !g is so rarely better or helpful that I wonder why I still sometimes bother.
Edit: I think the real problem is with ICANN. .com should have been kept for global or multinational sites, and the USA used .co.us and .us generally for sites of national interest, as France uses .fr, Germany .de and UK .uk etc.