How to host the Primary Domain from a subfolder (.htaccess)
https://my.bluehost.com/hosting/help/347

Modifying the .htaccess

The following code will need to be added to the .htaccess file in the public_html folder of your hosting account. You will need to insert the following code block and make modifications as noted in the (#) comments.

You will need to change the two instances of example.com to your domain, and the three instances of subdirectory to the folder where you want your site.


# BlueHost.com 
# .htaccess main domain to subdirectory redirect 
# Do not change this line. 
RewriteEngine on 
# Change example.com to be your main domain. 
RewriteCond %{HTTP_HOST} ^(www.)?example.com$ 
# Change 'subdirectory' to be the directory you will use for your main domain. 
RewriteCond %{REQUEST_URI} !^/subdirectory/ 
# Don't change the following two lines. 
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteCond %{REQUEST_FILENAME} !-d 
# Change 'subdirectory' to be the directory you will use for your main domain. 
RewriteRule ^(.*)$ /subdirectory/$1 
# Change example.com to be your main domain again. 
# Change 'subdirectory' to be the directory you will use for your main domain 
# followed by / then the main file for your site, index.php, index.html, etc. 
RewriteCond %{HTTP_HOST} ^(www.)?example.com$ 
RewriteRule ^(/)?$ subdirectory/index.html [L]


Visitors to your Web site will not be able to tell that your main domain is using a subdirectory, they will still see the Web site address as http://www.example.com/page.html.

Please note that this will not work with some website software. You may also need to modify the $base_url, $live_site or other configuration settings to finish the process.