How to Find a Leprechaun with GIS Software

March 16th, 2007, I laid a trap. Like many schools in New England, my classmates and I scattered leprechaun traps around the kindergarten classroom set with bits of gold or Lucky Charms™ marshmallows, anything to catch the eye of a sneaky red-haired man. We had worked for days with shoe boxes, construction paper, and beads to devise the perfect trap. When we raced into class on St. Patrick’s Day the room was in disarray; cereal had been eaten and gold beads were ripped from their pipe-cleaner holders. But not a single box was able to catch the leprechaun.

It has been a few years since I have whipped out my arts and crafts bin to redeem my 6-year-old self. Since then, I’ve learned a thing or two and gotten a couple of degrees, all of which make me better equipped to outsmart the mischievous Irish folklore. I got to thinking, maybe an elementary school in the suburbs wasn’t the right location to catch a leprechaun. Enough with the sparkles and shoe-boxes, I have GIS now. I believe that analyzing St. Patty’s Day staples across the continental United States will help to narrow down the best places to find a leprechaun.

Searching for Shamrocks

When I think of St. Patrick’s Day, the first thing that comes to mind is shamrocks. This symbol, also known as a clover, is like a good calling card for the little Irish mascot. Using observations recorded to iNaturalist, I mapped clover sightings in 2024. I created a density map in Global Mapper® from the observations to visualize the parts of the United States (US) that have the highest concentration of clovers. The West Coast, specifically California, as well as the East Coast, have the highest concentrations of shamrocks, perfect for a leprechaun to call home.

I have no evidence to support my theory, however I suspect that many leprechauns are not homebodies, therefore they won’t be lounging around all day in a sunny (or snowy in New England) clover field. This begs the question, where do these mischiefs go for fun?

Lucky Landmarks

Falling back once again on St. Patrick’s Day staples, I decided to pull places around the country that sound lucky. In particular, I looked at places that contained lucky, shamrock, gold or rainbow in their name. Using the USGS GeoName Database, I was able to pull lakes, towns, and other geographical features with Irish-sounding names into CSV files. Global Mapper enabled me to visualize these points with customized festive symbols.

Based on the distribution of features, California once again seems like a hot-spot for gold-minded leprechauns. Colorado has a lot of rainbows, Kentucky and Oregon seem to be quite lucky, and the Chesapeake shores love shamrocks.

Pass Me a Pint

I imagine that mischief and pranks can be exhausting. If leprechauns are anything like my Irish ancestors, they must love to relax at the end of the day with a nice, cold beer. This conclusion led me to pull the density of breweries throughout the United States. The US Census keeps records of businesses and industries and uses the North American Industry Classification System (NAICS) to organize the type of establishment. If you want to replicate my investigation, breweries are classified as NAICS code 312120.

To visualize the statistics provided by the US Census, I joined the CSV with a shapefile of US state vectors with the Global Mapper attribute editor. This allowed me to create a thematic map based on the attribute of my choice such as number of breweries. I wanted to take the data a step further and understand the density of breweries, or the number of breweries in comparison to the area. The attribute calculator made it easy to calculate and display this new attribute. While California by far has the highest quantity of breweries, factoring the size of each state more accurately represents the accessibility of beer. In the Northeastern Seaboard, a leprechaun would not have to look hard to find a refreshing cold one.

I cannot promise that there will be gold at the end of the rainbow, or that a leprechaun likes local draft beer, but I can guarantee that Global Mapper can make your treasure hunt more efficient. To learn more about the tools that would have helped your childhood quests, and can improve your workflows today visit our website, and try Global Mapper free for 14 days.

References:

• “Geographic Names Information System.” Edits.nationalmap.gov,
  edits.nationalmap.gov/apps/gaz-domestic/public/search/names.
• “Observations.” INaturalist, 2023,
  www.inaturalist.org/observations?d1=01%2F01%2F2024&d2=12%2F31%2F2024&place_id=1&subview=map&taxon_id=51876. Accessed 14 Mar. 2025.
  States, United.
• “Explore Census Data.” Census.gov, 2025,
  data.census.gov/table?q=312120&g=010XX00US. Accessed 14 Mar. 2025.