(NEXSTAR) — St. Patrick’s Day is nearly here, meaning those with Irish ancestry (and those without) will soon be sipping green beer, eating corned beef, and checking their leprechaun traps.

St. Patrick’s Day, March 17 (Sunday this year), is intended as a religious holiday, paying tribute to St. Patrick, who brought Christianity to Ireland in the 5th century. 

The U.S. Census Bureau reports the world’s first St. Paddy’s Day parade was held in 1762 in New York City, but the area isn’t as Irish as some other parts of the country have become. 

As a whole, about 30.7 million U.S. residents — or slightly more than 9% — claim to be at least partially Irish, Census data shows. 

It's a bit lower in Louisiana, with 6.3% of residents, or 288,803, reporting Irish ancestry.

The state with the most residents claiming Irish ancestry is California, which is home to nearly 2.2 million people claiming Irish ancestry, according to the Census’ 2022 American Community Survey 1-year estimates. The Golden State just edged out New York, which is home to a little over 2 million Irish or partially Irish residents.

The five states with the most residents of Irish descent, based on the latest Census data, are, unsurprisingly, also among the most populated: 

1. California
2. New York
3. Pennsylvania
4. Florida
5. Texas

While these states have “the most smiling Irish eyes,” there are states with higher overall densities of people with connections to Ireland. 

New Hampshire holds the top spot in that category: Nearly 20% of the state’s residents say they have Irish roots. The most Irish-dense states are all in the Northeast: 

1. New Hampshire: 19.2%
2. Massachusetts: 18.3%
3. Vermont: 16.5%
4. Rhode Island: 16.2%
5. Maine: 15.4%

Pennsylvania was close behind, with roughly 14.6% of its population sporting Irish ancestry. 

The interactive map below shows each state's population percentage of Irish or partially Irish residents.

Of any county in the U.S., it’s Cook County, which covers Chicago and the surrounding metro area, that has the highest density of Irish residents. Five-year estimates from the Census show more than 438,000 of the county’s 5 million residents claim to be of Irish descent. 

The interactive map below, released by the Census Bureau in 2021, shows the percentage of each county's population that reported having Irish ancestry.

According to the U.S. Census Bureau, all 3,142 counties in the U.S. have residents with Irish ancestry.

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