It is widely held that there are six Celtic nations. These are: Brittany (Breizh), Cornwall (Kernow), Wales (Cymru), Scotland (Alba), Ireland (Éire), and the Isle of Man.
I’d like to suggest another two.
Firstly, England. Unlike the aforementioned it has lost much of its obvious Celtic heritage, but the ‘shadows’ of that influence are still there, if you know where to look, and here’s one example: When in London, I live just 150 yards/meters from the River Thames. It was originally called Tamesis, and that was/is the name of the local Celtic goddess. She was ‘replaced’ in later, patriarchal times, with the god Llud, from which Ludgate Hill in central London, gets its name. But, there’s more.
Secondly, I’d suggest you and where you live as a Celtic enclave. Celts were adventurers and travelled afar. Not only by generations of marriage did their physical DNA move around the globe, but so did Celtic thought and religion. ‘Spiritual adoption’ can also make one a latter-day Celt. They were, indeed are, an inclusive, hospitable, family-orientated people.
I’ve met Canadian Celts, American Druids, Norwegian Light-Workers with similar beliefs, and conversed with Celtic Wiccans in Australia and Turkey etc. And now, you! Welcome, Celt!