This is a fantastic site, the "National Library of Scotland", and this is their interactive map system.  

We have permission to embed this page from the NLS, and, in using this system from our site, you the "user" agree not to copy images, resell images, use in any form any of the images in a commercial endeavor, doing so, you the "user" are solely responsible, not Clan MacLellan or Clan MacLellan Ancestry.

                                         "Please Do Not Copy Images"

To the left is the search and map selection tool, to use, 1. Select a location, or, 2. Select a county, 3. Select map overlay year. Use the "Change Transparency of Overlay" move the blue slider to the right will display the map of the area as it is today; slide it to the right back to the map overlay.

I found the "OS Six Inch, 1843 - 1882" is the best one and 80% of the time an obscure location will be on this map. 

I have been using this map system in conjunction with the "Mapping Project".