A couple weeks ago, Google opened up Google Map Maker again for the first time in a few months since they closed it down in May over embarrassing edits.
A couple weeks ago, they opened editing with the new guidelines in Bangladesh, Brazil, Canada, India, Philippines and Ukraine regions.
Now, Google has expanded it to a total of 45 countries including the United States.
Pavithra Kanakarajan, Product Manager, Google Map Maker, said in Google Map Maker Help thread that this went live today. She said "as part of the second phase of Map Maker’s reopening, 45 more countries are open for editing starting today."
If you go to Google Map Maker, you can search to see which countries are supported or not.
Google did disable polygon editing. Pavithra Kanakarajan said, "we have temporarily disabled the ability to add or edit geometries of polygons." She added, "you will, however, be able to edit other attributes such as names on polygonal features."
Forum discussion at Google Map Maker Help.