I would like to get your opinions on which region to choose if my traffic will mostly be from New York. I am currently using northamerica-northeast1 and was wondering if I should've used us-west1 or whichever other datacenters nearest to NY (which I have no idea of). I hope my question makes sense. Thanks!
northamerica-northeast1 is located in Montréal, Québec, Canada, approximately 600 km away.
The closest datacenter to New York City is
us-east4, located in Ashburn, Northern Virginia - approximately 400 km away. If your traffic is coming mainly from New York this will ensure the lowest latencies and possibly slightly higher transfer speeds.
I would say both locations are totally fine, unless the potential latency and speed improvements overweight the hassle of migrating your instance(s).
You can consult all the available regions for Compute in Google's official documentation.