HISTORIC ST. JOHN'S
In March, 2011, the Town of Islip erected this historical marker in front of St. John Nepomucene Church.
The Society is grateful to the town and to Mr. Robert Finnegan, the Town Historian, for their efforts in obtaining the marker.
The first Mass was celebrated in Bohemia in 1869 in the one-room school house on the corner of Church Street and Smithtown Avenue. However, when the Catholics placed religious pictures on the walls, there were complaints to the school board and the congregation was evicted.  After that, the congregation gathered for Mass wherever it was convenient.
Fr. James Bobier had become pastor of St. Patrick's church in Bay Shore in 1883. He began to visit Catholics in neighboring communities. In 1885, he succeeded in building a small chapel on the corner of Church Street and Locust Avenue. 36 feet by 20 feet, it held 104 people in 13 rows of pews. Five acres of land had been donated by the estate of Alexander Wallis and Frederick Coe.
St. John's church as built. Originally, the entry was through the bell tower and was wide enough for only one person. In 1922, the sides of the entrance were extended to give the church its present rectangular shape.
Over the years,, he congregation was  cared for by priests from St. Patrick, Bay Shore; St. Mary, East Islip and St. Lawrence, Sayville until 1919 when Fr. Wenceslaus Kroupa became the first resident pastor.
Fr. Kroupa with the First Communion class of 1919. Front: Helen Potuzak, Magda Schwab, Rose Klem, Anna Kurka, Walter Bartik. Back: Agnes Siska, Beatrice Siska, Elsie Bartik, Rose Siska. The two altar boys were from Sayville.
Who was St. John Nepomucene?
John Wolflin was born around 1345 in the town of Nepomuk (hence, Nepo-mucene) in the modern Czech Republic. As a high official, he became involved in disputes with the king over matters of both church and state. He was also confessor to the queen. According to legend, the king demanded that John reveal what the queen had spoken of in confession. John refused, was beheaded and his body thrown into the Vltava River that flows through Prague. Further legend tells that a light appeared over the water revealing where John's body was. John is the patron of what is called the "seal of the confessional," i.e. that no priest may reveal what has been told in confession. Thus, he is usually portrayed with his finger to his lips. Very popular in the Czech lands and in areas in this country where Czech immigrants settled, his feast day is May 16.
The statue of St. John Nepomucene that stood in the first church.
From the 1930s, the church with the parish school and rectory, which was originally a private home. The convent is next to the rectory.
The school opened in 1927 under the direction of the School Sisters of Notre Dame. It burned in 1957 and was replaced by a new school. This was regionalized with the Catholic school in Sayville in 1992.
St. John's church today. It serves the parish as a youth center. The congregation worships in the new church, accommodating 600, that was dedicated in 1981.
The original bell monument in front of the old church
Below
The memorial plaque with the bell
Inside the church in the 1940s
Most of the information here is from a pamphlet with the history of the parish written in 2005.