How do I locate a flies nest?

They may be nesting inside your window frames. Check for small holes and or air gaps.

Hi Lisa, here are a couple of links that should help

https://www.orkin.com/flies/house-fly/house-fly-larvae

https://www.youtube.com/watch?v=LzNASylLO0k

House flies do not build nests. The female fly lays her eggs in rotting organic matter, such as garbage, feces, or animal carcasses. Maggots hatch out of the eggs, eat the rotten material around them, and grow. When they are finished growing, they crawl away to enter a pupal state.

BUT...watch this.... https://www.youtube.com/watch?v=LzNASylLO0k

My outdoor kitchen had flies, as my neighbor raises cows and the manure they produce attracts them. So I use the old Shell NO PEST strip, available from amazon, Walmart, Kroger,etc. and it works like a charm. I’m seventy now, and my mom used these much the same way I do. In front of my doors and in my out buildings and I’m not bothered with flies anymore. I love looking at the cows, but had to remedy the problem. I’m sure there are the usual nay-sayers out there, but they are city folk😊. Good luck with your problem.

Thanks to everyone for your assistance! Hopefully this will be the last summer for those pesky flies inside the house!