SwiftNinjaPro

A Plugin That only allows whitelisted IP’s, or optionally whitelisted browsers, to access wp-login. 
This plugin does Not effect front-end login plugins. 
If an IP is not whitelisted, the wp-login page will be killed and replaced with a message saying “your IP/Browser is not whitelisted”, or optionally redirect the user to 404 page instead.
A better way to hide wp-login. You can add a list of admin IP’s to this plugin, where you want to allow usage of wp-login. 
Even if you have other users that login, its better to use another plugin for a more secure front end login, and this plugin will only allow a specific list of IP’s to access the wp-login page. 
You can also (optionally) have this plugin attempt to redirect anyone to 404 page, if they try and access wp-login without the right IP. 
You can also choose to disable the 404 redirect, and instead tell users there IP is not whitelisted, and that they should contact the admin if this is in error. 
The plugin does Not block wp-admin, so once logged in, you can still edit your site on the go. 
The plugin also has an option to whitelist your favorite common browsers to wp-login. This means you can keep users from accessing the wp-login page, simply because there using Internet Explore, and not what you chose to allow. 
There is another option (which may return false positives), that attempts to check if the source of an IP is commonly used by a proxy server, and can block proxy IP’s to try and reduce spoofing.

WP-Login and WP-Admin Whitelist

A Plugin That only allows whitelisted IP's, or optionally whitelisted browsers, to access wp-login, or optionally wp-admin.

Anthony

This plugin will limit access to the site. Only visitors with a cookie token will be able to access the public website. Visitors without the cookie will see a “coming soon” style of page.
You can customise the “coming soon” content, and you can change the way tokens work. Visit yoursite.com/?add_token to receive the token allowing you to see the site. To remove the limited access, simply disable this plugin.
By default, the token is “letmein”. So use these links: 
site.com?letmein 
site.com?takemeoff
This plugin is useful when you’re developing your site. You can work on your live web server without having your site open to the public.

Token Access

Limit access to the site to those with a cookie token.  Visitors without the cookie see a customisable "coming soon" style of page.

WP-Login and WP-Admin Whitelist vs Token Access