I really love maps and I wanted to post here a wonderful place that integrates maps with the Griffith's Valuation. Check it out here. Not only do you get to see the original pages of the valuation, but those pages actually cite a map location, which I had not known before. You can then use that information to pull up a wonderful old map where you can zoom in and locate not only your townland, but also the property number as well. It couldn't get any better. I wrote to the people who run that website to thank them!
Much less impressive is a map I've been working on for various locations in County Armagh that apply to my Gillespie/Greer research. Click here to see my map, which is a work in progress. Townlands of interest include Lisnadill, Drumagaw, Cavanacaw, Ennislare, Farmacaffly, and Roghan in Armagh, and Emyvale in Monoghan. If you run across any of the following surnames in any of these places, please feel free to contact me: Gillespie, Greer/Grier, Wood/Woods, Donaldson, Diffin, Orr, and Rainey. I would love to compare notes.