NILES — Once, nuns walked down the hallways of St. Mary’s of the Immaculate Conception Church’s parish offices, 219 S. State St., when they were a convent. Now, Father Christian Johnston walks down a hallway lined with photographs depicting St. Mary’s 150-year history.

Johnston pauses in front of a few pictures lining a wall, showing the inside of the church in different decades. In some, its ceiling is raised. In others, it is lowered. In some, its features are ornate. In others, the design is simple.

While the church’s appearance, its community outreach and its parishioner numbers have changed, Johnston said the one thing has stayed the same: the kindness of the people that make up St. Mary’s.

“Each place is still its own parish, its own community, and it’s kind of nice that way,” he said.

St. Mary’s official anniversary is Dec. 11, 2020, but staff will host a series of events in 2020 to celebrate with its approximately 500 parishioners

Chief among them is an anniversary mass Sept. 27, with three services in English and one in Spanish. A catered dinner and games will follow.

Other events still in the works are a chili cook-off, a pilgrimage, an organ concert, a picnic, a historical presentation on Catholicism’s presence in Niles, a fiesta hosted by the church’s Latino group and a presence in the Four Flags Area Apple Festival parade. Johnston hopes to bring out a miniature St. Mary’s church float that has been in storage for the past two decades for the parade.

Johnston said he was also excited to recognize and celebrate with organizations that are tied closely with the church.

Among them is Scouts Troop 579, of Niles. The troop and the church have had a decades-long relationship, Johnston said, with the troop helping at many events. Johnston hopes to co-host an event with them.

Leslie Conyers, principal of St. Mary’s School, is excited to celebrate the anniversary as well. She hopes to create student activities around the anniversary and send her students to events the church hosts.

“The parishioners, the collection and the priest are just so supportive of making sure this building remains open, and that we are able to provide a Catholic education for this area,” Conyers said.

While the preschool to eighth-grade private school does not have a landmark anniversary to celebrate in 2020, — it turns 128 — Conyers said its day-to-day work that blends faith with regular school programming gives reason to celebrate.

“There’s compassion and caring and kindness and doing good and helping others,” she said. “It’s just being immersed in the faith.”

Other major extensions of the parish have come about after St. Mary’s was blessed and dedicated will join in on the celebrations, too. St. Mary’s Christian Service Center, a food pantry that serves everyone, regardless of faith, celebrated 30 years last year. Also last year, St. Mark Church, which splits the parish with St. Mary’s, celebrated 50 years.

While St. Mary’s own celebration nears a century and a half, its history goes back farther, Johnston said.

It began in 1847, 173 years ago. Friar Edward Sorin, the founder of the University of Notre Dame, began to construct St. Francis of Assisi Church close to where St. Mary’s 180-foot spirals tower over other buildings today.

After it was blessed in 1849, it became a parish in 1857, no longer a mission of Notre Dame. It soon became clear, however, that a larger church was needed to serve the community.

Thus, St. Mary’s was created.

Since its blessing in 1870, the church underwent major renovations in 1908, 1950 and 1976. More recently, in 2010, its sanctuary was repainted with more decorative elements. In 2012, the church interior was repainted.

In the past three years, the time Johnston has been with St. Mary’s, it received new organs. In the next few years, he hopes to update the church’s bells.

As the church received upgrades, the demography of its parishioners changed. A largely Irish and Italian presence decades ago made for a mix of heritage histories, including a strong Latinx presence.

Both Conyers and Johnston said that aside from anniversary celebrations, the importance of 2020 is not felt daily. They, other staff and parishioners have gone about business as usual, celebrating God, educating and serving others.