Everyone is honorary-Irish on March 17, donning green clothing and swigging green beers. But how many Minnesotans actually have Irish ancestry?

We started by looking at historic immigration trends, going back to the 1850 Census, which was the first time the Bureau started tracking, on a state level, where residents were born -- the best indication of how many immigrants a state has and where they're from.

The number of people living in Minnesota who were born in Ireland grew until 1890, and then started to fall as overall immigration from Europe trailed off. Over time, those original immigrants began to die faster than new Irish immigrants were arriving. Today, about 600 Minnesota residents were born in Ireland.

Minnesota isn't even close to the top of the list for Irish emigration -- that designation would go to New England states like Massachusetts. Minnesota is rightly known for German and Scandinavian heritage.

And when compared to immigrants from those countries, our Irish population was indeed small.

So, where do people with Irish heritage live now? We looked at the most recent American Community Survey data to find out.

The ACS counts ancestry a few different ways: It might ask for "first" or "second" ancestry, which looks for a predominance of a particular ethnicity. We instead used the table asking for "any" ancestry, meaning anyone who said they had at least some Irish ancestry would turn up.

On a county level, Le Sueur County was tops: 15 percent of its residents say they have some Irish blood. On the low end, only 4 percent of residents in Mahnomen County have Irish ancestry.

But when we dive in a little deeper, into "census tracts," which are smaller geographies similar to neighborhoods with roughly similar population sizes, we see a more obvious cluster turn up: In the Macalester-Groveland, Highland Park and West Seventh neighborhoods of St. Paul, and across the river in West St. Paul.

A cluster of blocks south of St. Clair Avenue between Cleveland and Fairview avenues has the highest concentration: One out of every three residents there say they have some Irish ancestry.

What do you see where you live? Do the numbers make sense? Let us know in the comments.

Data Drop is a weekly feature that uses data analysis and visualizations to explain, surprise, inform and entertain readers on topics relevant to Minnesotans. Do you have an idea you'd like us to explore? Contact MaryJo Webster