I have a Google My Map which lists places in the US. By default, the map zooms to the full US to include all places. I'd like to be able to link to specific focus/zoom levels (e.g. just places in NYC), but the URL doesn't change when I change focus in the UI. Is there any way to hack the URLs to do this?
Now I see that you specified "My Maps" which means you won't be editing your answer to include any code (since you don't have that ability with "My Maps"). Everything I've found from Google indicates that you aren't going to be able to do this. Evidence of inability to edit zoom level and center
However, I did find this link showing a method that would work for an embedded map (if your map is embedded in your website). This forum posting is similar to the link you posted in your comment. At first I thought that you wouldn't be able to enter that in the URL. I suspected that it would have to be embedded, but you commented that it works as a viewer (but not always in editor mode)! The code looks like this ...
<iframe src=".../embed?mid=...&z=12&ll=56.4567,-3.4567" ..