We know D.C. Get our free newsletter to stay in the know.

Why does it seem like there’s a church on every block of 16th Street NW from the White House all the way to Silver Spring? Walk up, say, Connecticut Avenue, and you’re lucky to find two churches and a synagogue by the time you hit Chevy Chase. What gives? Am I imagining this, or is 16th the District’s most devout thoroughfare?

You’re not imagining things: There is an average of more than five religious institutions per each of 16th Street NW’s seven-and-a-half miles stretching from Lafayette Park to the Maryland border.

Before the mid-19th century, you wouldn’t have seen so many churches, synagogues, and mosques on 16th Street; you’d have seen shanties. Prior to 1861, fewer than ten permanent structures of any size or classification appeared on the stretch. Only one of them was a church: St. John’s Church, across the street from the White House and Lafayette Park at 1525 H St. NW.

But the Civil War changed everything. As opportunistic Northerners poured into town to work in newly formed government bureaus, seek military contracts, or serve in the city’s hospitals, the number of people living in the city reached 140,000 by 1864—more than double the population in the 1860 census. And as people crowded into the city, they sparked rapid residential development along 16th Street.

In turn, that development led to the construction of churches, including the First Baptist Church, Church of the Holy City, and Foundry Methodist Church, as well as other community and national institutions. This happened not out of any grand design, but rather as a result of the developing population’s needs, says Bruce Yarnell, education outreach program manager of the District’s Office of Planning.

As the concentration of religious institutions grew, 16th Street came to be the go-to place for large national churches, Yarnell says.

For instance, All Souls Church, Unitarian—which John Quincy Adams, John Calhoun, and others founded as The First Unitarian Church in 1821—built its current building at 16th Street and Harvard Street NW in 1921 in recognition of 16th Street’s prominence as a location for national churches, says the church’s current pastor, the Rev. Robert M. Hardies.

Likewise, the Universalist Church of America (which would later merge with the Unitarian church) has its national representative, the Universalist National Memorial Church, at 16th and S, where it has been since 1930.

Every Monday, the ‘Huh?’ Bub takes your questions. Got one?