Following are default locations of nginx webroot with standard installations:

  • Ubuntu 12.04: /usr/share/nginx/www
  • Ubuntu 14.04: /usr/share/nginx/html
  • Mac OS (brew): /usr/local/var/www

On Ubuntu 14.04, the webroot is defined in

/etc/nginx/sites-enabled/default

You should something like:

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    root /usr/share/nginx/html;
    index index.html index.htm;
    ...
}

To change the webroot, simply change root to your preferred address, for example:

root /var/www

to change webroot to /var/www.