Q:

Where is Avengers HQ in the MCU?

Over the course of Phase II and Phase III of the MCU, the Avengers renovate a former Stark Industries storage facility north of New York City and use it as their headquarters. From shots showing the Hudson River and Manhattan in the distance, I think it’s somewhere in Rockland County, perhaps near Nyack. Can anybody place it more precisely?

A:

The only thing we know about the location is that it is an "abandoned Stark Industries warehouse located in Upstate New York" however, it's kind of impossible to pin down a definitive location as it was filmed in London, Norwich and Atlanta. 

A:

According to this site

As you can see from the Google satellite view, the location above matches the original photographic background plate to a ‘T’. I can solidly proclaim that the Avengers are headquartered in Esopus, New York!

For Captain America: Civil War the layout was changed slightly and the entire facility was placed into context of the Hudson River Valley. According to Cinefex #147, an aerial plate was shot of an actual plot of land along the Hudson River. Effects artists then placed the buildings into that plate. When I first saw the image of the plate from that issue, I thought it would be impossible to find the actual location. 

