Is there any way for your country of origin to know that you acquired U.S. citizenship thru naturalization if you don't tell them yourself? I mean, is there anything like a list of recently naturalized persons or does USCIS actively notify your country of origin?
Nope, the country of origin doesn't get any information from US agencies. The way they find out is when you travel to the country, or when you renew their passport (if they require proof of legal status in the US APART from a passport).