Hi JoefromCT and welcome to the forum
Where can you find INTJs? It's tricky because it varies with the INTJ, depending on their interests, their age group and probably their marital status. If an INTJ is single, you may find them at events if they're there with friends. But normally an INTJ will stick to his or her hobbies and our hobbies vary greatly. Not all of us are nerds, but the common denominator is that you'll find that we're very good at the hobbies we've chosen. We either love or hate something, so if you're lucky and find an INTJ where they can excel and do stuff they think is fun, we're more open and approachable in my experience.
Remember, we're not necessarily very good with normal social conduct and we're known to criticize openly, and it doesn't matter to us if it's the president itself, we'll criticize if we feel that there's something that needs improvement. I hope it doesn't put you off. We will not necessarily understand if and when someone flirts with us, so give us time to understand. If you connect with us over a hobby or something, we feel safe, but I've never assumed that I was flirted with and always the 'buddy' kind of girl, so you have to come on strong so we'll understand your intentions. (If you're looking for something romantic.) And even then we will doubt that you really meant what you said, and that you probably say the same thing to everyone etc.etc. (Yea, we can be kind of dense..)
I always used to think that it would've been most practical if single guys who were interested in me would wear a sign or just say it flat out, so I could think about whether I wanted to engage or not... Lol! We have no patience for social games. We can also be insecure and not understand our own value so to speak. I bet even a drop dead gorgeous INTJ would not know that they're gorgeous and refuse to play normal dating games. If you praise us for our intelligence or skills, you'll reach very far even if we dismiss what you say!
Good luck finding an awesome INTJ