FILE - Sign painters work on a portrait of Pope Francis, right, on the side of a New York City building. The pope visits the U.S. beginning September 22, with stops in Washington D.C., New York and Philadelphia.
FILE - Sign painters work on a portrait of Pope Francis, right, on the side of a New York City building. The pope visits the U.S. beginning September 22, with stops in Washington D.C., New York and Philadelphia.

New York City, one of the three U.S. cities Pope Francis will visit this week, is in a three-way tie as the most Catholic city in the United States, a religious institute's analysis found.

In Boston, New York and Pittsburgh, 36 percent of residents said they were Catholic, according to the Public Religion Research Institute's (PRRI) 2014 study, which ranked the largest religious groups in 30 major U.S. metropolitan areas -- those with populations of at least 50,000.

Philadelphia, where the pope plans to hold an outdoor Mass at which up to 2 million people are expected on September 27, and Chicago tie as the second-most Catholic city in the U.S., with 33 percent.

Washington, D.C., where Francis will canonize Junipero Serra on September 23 and address a joint session of the U.S. Congress on September 24, is in a three-way tie for 11th place, with 19 percent of residents who say they are Catholic.

In its study released in August, PRRI found Catholics, the religiously unaffiliated and Protestants are the top three religious groups, respectively, in the major metro areas.

It also found Rhode Island is the most Catholic state, with 44 percent of its population identifying with the church.

Here are cities with the largest Catholic populations:

1.    Boston             36%
1.    New York City  36%
1.    Pittsburgh        36%

2.    Chicago           33%
2.    Philadelphia     33%   

3.    Los Angeles     31%
3.    Miami                31%

4.    Las Vegas        27%
4.    Minneapolis / St. Paul    27%

5.    Milwaukee        26%
5.    Phoenix            26%
5.    San Francisco 26%

6.    St. Louis           25%

7.    Cleveland         23%
7.    Detroit              23%
7.     Houston          23%

8.     Columbus       22%

9.     Cincinnati        21%   

10.     Denver          20%

11.     Dallas            19%   
11.     Tampa / St. Petersburg    19%   
11.     Washington, D.C.             19%

Source: Public Religion Research Institute, American Values Atlas, 2014